Vehicle Drive Control for Negative Torque Abnormality Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing control devices for vehicle drive systems with rotating electrical machines do not adequately detect and mitigate unintended negative torque, which can lead to unstable vehicle travel.
Innovation Solution
A control device that sets a torque threshold value based on the relationship between the actual rotational speed and target torque of the rotating electrical machine, allowing for appropriate determination of negative torque abnormalities and implementation of stop control to reduce drive power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed torque threshold is used to determine negative torque abnormality, then the determination rule is simple, but the determination accuracy deteriorates under varying operational conditions
Solution Approach 1:
The patent applies dynamics by making the torque threshold dynamic rather than fixed. The threshold is adjusted based on the actual rotational speed of the rotating electrical machine, allowing the determination criterion to adapt to varying operational conditions. This resolves the contradiction by maintaining simple determination logic while improving accuracy across different speed ranges.
Solution Approach 2:
The patent changes the parameter used for threshold determination from a fixed value to a value that varies with rotational speed. By establishing a relationship between the torque threshold and the actual rotational speed, the system achieves accurate negative torque abnormality determination across different operating conditions without complicating the overall determination process.
2Productivity
If the rotating electrical machine continues to operate during negative torque abnormality, then productivity is maintained, but vehicle traveling stability deteriorates
Solution Approach 1:
The patent implements feedback by continuously monitoring the actual torque and comparing it against the dynamic threshold based on rotational speed. When negative torque abnormality is detected, the system provides feedback to stop the rotating electrical machine, preventing unstable vehicle traveling while maintaining operational safety. This resolves the contradiction by enabling continuous operation under normal conditions while ensuring stability when abnormalities occur.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A control target for a control device (10) is a vehicle drive device (1) including a rotating electrical machine (MG), and the control device (10) includes: an actual rotational speed obtaining part (14) that obtains an actual rotational speed (Nm) which is an actual rotational speed of the rotating electrical machine (MG); an actual torque obtaining part (15) that obtains actual torque (Tm) which is actual torque of the rotating electrical machine (MG); and a determining part (16) that determines a state of the rotating electrical machine (MG). The determining part (16) determines that the state of the rotating electrical machine (MG) is a negative torque abnormality, when the actual torque (Tm) has a negative value smaller than a torque threshold value (THt) set based on a relationship between the actual rotational speed (Nm) and target torque (Tmt) of the rotating electrical machine (MG).