Electric Vehicle Control Device Power Relay Fusion Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional electric vehicle control devices risk fuse failure in power relays due to microcomputer errors, leading to unintended power relay shutdown during reset processes, especially during reprogramming or low voltage scenarios.
Innovation Solution
An electric vehicle control device with two microcomputers sharing a power source, allowing independent program rewriting and mutual operation monitoring, performs a power shut-off reset process that turns off power relays only when a microcomputer error is identified, ensuring the relays are powered off before resetting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reset process is performed when a microcomputer operation error is identified, then the microcomputer operation reliability is improved, but the power relay switch contacts may fuse due to unintended power shutdown
Solution Approach 1:
The control device determines whether power is flowing through the onboard power system before performing the reset process. If power flow is detected, the reset process is postponed or handled differently to avoid shutting off the power relay when power is actively flowing, thus preventing switch contact fusion while still ensuring microcomputer operation reliability.
2Reliability
If the power relay is turned off during reset process, then the fail-safe function is improved, but the power relay switch contacts may fuse due to sparking
Solution Approach 1:
The system checks the power flow state before executing the reset process that would turn off the power relay. By determining in advance whether power is flowing through the onboard power system, the control device can avoid turning off the power relay during active power flow, thereby eliminating sparking at switch contacts while maintaining the fail-safe function when actually needed.
3Adaptability or versatility
If a reset process is performed during reprogramming, then the control program updating is completed, but the power relay may be forcibly turned off causing system disruption
Solution Approach 1:
Before performing a reset process during or after reprogramming, the control device determines whether power is currently flowing through the onboard power system. If power flow is detected, the reset process is modified or delayed to prevent forcible power relay shutdown, thus maintaining power system stability while still allowing control program updating to complete successfully.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The present invention prevents fusion in a power relay when a reset is performed as the result of a microcomputer operation error not caused by a microcomputer error being identified. Provided are a first microcomputer (11) and a second microcomputer (12) that share a power source, have separate control functions, and allow for independent rewriting of their respective control programs, and reset process means for monitoring mutual microcomputer operation and performing a reset process that turns off power relays (31), (32) belonging to an onboard power system when an microcomputer operation error is identified. In this electric car control device, the reset process means comprises a power shut-off reset process unit for performing a reset process that shuts off the flow of power through the onboard power system and turns off the power relays (31), (32) in this powered-off state when resetting due to a microcomputer operation error not caused by a microcomputer error being identified.