Parallel Battery Pack Converter Fault Isolation Under Power Derating
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Non-optimal switch conditions in a DC-DC converter can disrupt the operation of a vehicle's electrical system, necessitating a strategy to maintain functionality.
Innovation Solution
A method and system that measure switch voltage, determine switch status, disable affected legs, derate power, and utilize alternative power sources to ensure continued operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the converter operates at full power, then the productivity is improved, but the reliability deteriorates when a switch operates in non-optimal condition
Solution Approach 1:
When a switch operates in non-optimal condition, the system applies partial action by derating the converter power to a percentage of full power (e.g., 2/3 or 1/3) rather than shutting down completely. This allows the system to continue operating at reduced capacity, maintaining partial productivity while ensuring safety and reliability.
Solution Approach 2:
The converter is divided into multiple legs, and when a switch fault is detected in one leg, only that specific leg is disabled while other legs continue to operate. This segmentation allows the system to isolate the faulty component and maintain functionality through remaining healthy segments.
2Reliability
If the switch forms an open circuit, then the reliability is improved by isolating the fault, but the productivity deteriorates due to power derating
Solution Approach 1:
When a switch forms an open circuit, the faulty switch and its associated leg are extracted or removed from the operational circuit. The system disables the specific leg containing the open-circuit switch, isolating the fault to prevent it from affecting other parts of the system.
Solution Approach 2:
The system accepts reduced power output (derating to 2/3 or 1/3 of full power) as a necessary compromise to maintain reliability. By operating with fewer functional legs rather than shutting down completely, the system achieves partial productivity while ensuring safe operation.
3Reliability
If the converter is disconnected from the energy cell, then the reliability is improved by isolating the fault, but the productivity deteriorates due to loss of high energy density power source
Solution Approach 1:
The system segments the power delivery path by selectively disconnecting only the affected leg or phase from the energy cell, rather than disconnecting the entire converter. This allows the converter to remain connected to the high energy density power source while isolating specific faulty components.
Solution Approach 2:
The system maintains partial connection to the energy cell through remaining healthy legs, accepting reduced power delivery capability rather than complete disconnection. This partial operation allows continued access to high energy density power while maintaining fault isolation.
Data Source
AI summary
A vehicle includes an electrical load and an electrical system for providing power to the electrical load. The electrical system includes a converter including at least one leg, at least one inductor and a pyro switch between the at least one leg and the at least one inductor, an energy cell coupled to the converter at a first side of the converter, a propulsion cell coupled to a second side of the converter, and a processor. The processor is configured to measure a voltage at a switch of the converter, determine a switch status of the switch based on the voltage, operate the pyro switch to disable the at least one leg that includes the switch, derate a power of the converter to a percentage of a full power of the converter, and provide the derated power to the electrical load.