Dual-Branch EV Power Supply for Fault-Tolerant DC/DC Conversion
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Solution Overview
Problem
Existing systems for electrical power supply in electric vehicles lack reliability and safety for use with highly automated driver assist systems, particularly in high-voltage onboard networks.
Innovation Solution
A system comprising a high-voltage battery with two branches connected in series, a cascading multistage DC/DC converter, and a galvanically isolated main converter, which provides a stable and reliable power supply to both high-voltage and low-voltage onboard networks, ensuring continued operation even in the event of a fault.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a DC/DC converter is connected after the battery contactor to the full system voltage, then the converter can be simplified in structure, but the system reliability and safety for highly automated driver assist systems deteriorates
Solution Approach 1:
The battery system is segmented into two independent branches (first branch and second branch), each capable of independently powering the DC/DC converter. This segmentation allows the system to maintain power supply functionality even when one branch fails, thereby improving reliability without significantly increasing overall system complexity
Solution Approach 2:
The system incorporates redundant battery branches and control mechanisms in advance to cushion against potential failures. The control unit is pre-configured to detect faults and automatically switch between branches, ensuring continuous safe operation before actual failures occur
2Device complexity
If the HV network is not subject to ASIL safety classification, then the system design is simplified, but the suitability for highly automated driver assist systems deteriorates
Solution Approach 1:
The safety management system is designed to be dynamic and adaptive rather than static. The control unit can adjust safety parameters and operational modes based on real-time system state and fault conditions, allowing the system to meet ASIL requirements without rigid structural complexity
Solution Approach 2:
The battery system and control unit are designed with multi-functionality to serve both high-voltage power supply and safety classification requirements. The same hardware infrastructure supports both operational functions and safety monitoring, eliminating the need for separate dedicated safety systems
3Device complexity
If a single battery branch is used, then the system structure is simplified, but the availability of power supply deteriorates in fault conditions
Solution Approach 1:
The battery system is divided into two independent branches with separate connection paths to the DC/DC converter. This segmentation creates redundant power supply paths, ensuring that if one branch fails, the other can continue to provide power, thereby maintaining system availability without excessive complexity
Solution Approach 2:
The system can dynamically change operational parameters such as voltage levels and current distribution between branches based on system conditions. This flexibility allows optimal power distribution and fault tolerance while maintaining a relatively simple overall structure
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
The system achieves enhanced availability and efficiency of the power supply to the low-voltage onboard network, ensuring continued operation even in fault conditions, while meeting safety criteria for highly automated systems.
Implementation Method 1
a first switching circuit (21), which receives an input DC voltage and puts out a first DC voltage
Implementation Method 2
a resonance circuit (23) having a second circuit (33), which receives the first DC voltage and puts out an output DC voltage
Data Source
AI summary
A system for the electrical power supply of a vehicle and a method for the electrical power supply of a vehicle are described.