Hybrid Vehicle Emergency Travel Control via DC-DC Converter Abnormality Detection
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Solution Overview
Problem
Hybrid electric vehicles face safety risks due to deteriorated braking performance when abnormalities occur in the low voltage DC-DC converter or the voltage of the low voltage battery deviates from the operational range of the braking device, leading to potential accidents.
Innovation Solution
A system and method for controlling the travel of a hybrid electric vehicle in emergencies by determining abnormalities in the low voltage DC-DC converter and setting restricted vehicle speeds and maximum torque to ensure stable braking power, using a vehicle controller to manage torque and mechanical braking power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high voltage power is used to increase system power for motor acceleration and electrical components, then power supply capability is improved, but safety risk increases due to electric shock hazard
Solution Approach 1:
The patent divides the electrical power system into two separate voltage levels: a high voltage battery (250V or more) for power-intensive components like the motor and air conditioner, and a low voltage battery (12V) for general electrical assemblies. This segmentation allows the system to utilize high voltage power benefits while isolating low voltage components from electric shock hazards, thereby improving overall system safety.
2Loss of energy
If a low voltage DC-DC converter is used to charge the low voltage battery from high voltage, then power conversion efficiency is improved, but system reliability deteriorates when the converter malfunctions
Solution Approach 1:
The patent incorporates a monitoring mechanism that detects abnormalities in the low voltage DC-DC converter in advance. When a malfunction is detected, the system proactively switches to an alternative power supply mode before the converter failure completely compromises the low voltage battery charging, thereby maintaining system reliability while having previously achieved efficient power conversion.
Solution Approach 2:
The system prepares alternative power supply pathways and control strategies in advance to cushion against potential DC-DC converter failures. By having pre-established backup mechanisms and monitoring systems, the patent ensures that converter malfunction does not lead to complete system failure, thus maintaining reliability while benefiting from efficient power conversion during normal operation.
3Adaptability or versatility
If the low voltage battery voltage drops below the operational range of the braking device, then power supply adaptability is reduced, but braking performance deteriorates seriously
Solution Approach 1:
The patent implements a feedback mechanism that continuously monitors the low voltage battery voltage level. When the voltage drops below the operational range required for the braking device, the system detects this condition and triggers a response to switch to mechanical braking or alternative power supply, thereby preventing braking performance deterioration while adapting to varying power supply conditions.
Solution Approach 2:
The system dynamically adjusts the braking mechanism based on real-time voltage conditions. When low voltage battery voltage is sufficient, the system uses electrical braking; when voltage drops below operational thresholds, the system transitions to mechanical braking. This dynamic adaptation ensures reliable braking performance across varying power supply conditions while maintaining power supply adaptability.
4Reliability
If restricted vehicle speed and maximum torque are set when abnormality occurs, then braking safety is improved, but vehicle productivity decreases
Solution Approach 1:
The patent applies partial restriction measures rather than complete vehicle shutdown when abnormalities are detected. By setting restricted vehicle speed and maximum torque limits instead of halting operation entirely, the system maintains sufficient braking safety while preserving partial vehicle functionality and productivity, allowing continued operation under controlled conditions.
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 solution effectively restricts vehicle speed and torque to ensure safe braking performance even when abnormalities occur, preventing performance deterioration and ensuring driver safety by implementing mechanical braking power efficiently.
Implementation Method 1
a low voltage DC-DC converter for converting high voltage of a high voltage battery into low voltage, and supplying the low voltage to a low voltage battery
Implementation Method 2
a braking device for receiving power from the low voltage battery and then applying a braking signal to a driving motor
Data Source
AI summary
Disclosed herein is a method of controlling the travel of a hybrid electric vehicle in an emergency. It is determined whether an abnormality has occurred in a low voltage Direct Current-Direct Current (DC-DC) converter. When it is determined that an abnormality has occurred in the low voltage DC-DC converter, it is determined whether the voltage of a low voltage battery has deviated from the operational voltage range of a braking device. When the voltage of the low voltage battery has deviated from the operational voltage range of the braking device, a restricted vehicle speed is set to take into account mechanical braking power. A maximum torque used to restrict the torque of a driving motor is set based on the set restricted vehicle speed.