Dual DC/DC Low-Voltage Supply on a Common Traction Bus
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Solution Overview
Problem
Existing high voltage traction systems face challenges related to safety, reliability, and efficiency due to the complexity of managing multiple power packs and loads, with electrical faults potentially propagating and affecting other components, and there is a need for improved protection against electrical faults, especially in low voltage systems that power critical vehicle safety systems.
Innovation Solution
A high voltage traction system with a common traction voltage bus and parallelly arranged battery packs, featuring separate first and second connection lines for the low voltage system, each with DC/DC converters and protection fuses, along with individual load connectors and contactors, to provide redundancy and protection against electrical faults, ensuring the low voltage system remains operational even if one connection fails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple battery packs are parallelly connected to a common traction voltage bus to meet higher power requirements and provide redundancy, then the power supply capability and system redundancy are improved, but the complexity of managing multiple power packs and loads increases, and electrical faults may propagate through the system
Solution Approach 1:
The patent segments the electrical system into separate high voltage domain and low voltage domain, with dedicated connection lines for each domain. The high voltage battery packs are connected to the common traction voltage bus, while the low voltage system has its own separate connection lines with individual protection, preventing fault propagation between domains and reducing management complexity.
2Reliability
If individual protection devices are added to each connection line to prevent fault propagation, then the protection against electrical faults is improved, but the device complexity and number of components increase
Solution Approach 1:
The patent introduces domain protection units as intermediary devices that act as mediators between the high voltage domain and low voltage domain. These protection units include protection fuses and contactors that automatically isolate faults, providing robust protection without requiring complex control logic or multiple individual protection devices for each component.
3Reliability
If separate connection lines with DC/DC converters are provided for the low voltage system to ensure continuous operation, then the availability and safety of the low voltage system are improved, but the device complexity and cost increase
Solution Approach 1:
The patent applies local quality by providing dedicated separate connection lines specifically for the low voltage system, with local DC/DC converters and protection devices positioned at strategic points. This ensures that the low voltage system, which powers critical safety functions, has enhanced reliability and continuous operation capability without complicating the entire system architecture.
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 enhances the reliability and safety of low voltage systems by providing redundancy and protection against electrical faults, aligning with automotive safety standards, ensuring continuous operation and compliance with ISO 26262, and improving power distribution efficiency.
Implementation Method 1
a first DC/DC converter, and a second connection line arranged separately and in parallel to the first connection line, the second connection line comprising a second safety connector connected in series with a second DC/DC converter
Data Source
AI summary
A high voltage traction system for a vehicle has: a common traction voltage bus; a plurality of battery packs connectable to the common traction voltage bus; at least one load connected to, and powered by, the battery packs via the common traction voltage bus; a low voltage system connected to, and powered by, the battery packs via the common traction voltage bus. The low voltage system is connected to the common traction voltage bus by an individual safety connection comprising a first connection line including a first safety connector connected in series with a first DC/DC converter, and a second connection line arranged separately and in parallel to the first connection line. The second connection line includes a second safety connector connected in series with a second DC/DC converter.