Motor Coil Abnormality Detection in Electric Vehicles
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Solution Overview
Problem
In electric vehicles with in-wheel motor drive systems, existing methods are inadequate for detecting motor coil abnormalities both during traveling and non-traveling periods, which can lead to instability and safety issues if not addressed promptly.
Innovation Solution
An apparatus and method that include a start-up abnormality detection section and a travel abnormality detection section to monitor coil temperature, resistance, and insulation resistance, as well as the relationship between motor applied voltage and current, allowing for the identification of abnormalities before or during vehicle travel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If motor temperature monitoring is performed during vehicle travel to detect overload, then motor reliability is improved, but motor coil abnormalities cannot be detected during non-traveling periods
Solution Approach 1:
The patent applies preliminary action by performing motor coil abnormality detection during the non-traveling period (startup phase) before the vehicle begins operation. The controller measures coil resistance and compares it against threshold values to detect abnormalities in advance, enabling preventive maintenance before the vehicle is driven. This resolves the contradiction by shifting part of the detection activity from during-travel monitoring to pre-travel inspection.
2Measurement precision
If detailed diagnosis is performed during vehicle startup, then motor coil abnormalities can be detected early, but additional measurement time and complexity are required
Solution Approach 1:
The patent implements self-service by utilizing the existing motor control system and its built-in measurement capabilities to perform self-diagnosis of coil abnormalities. The controller uses the same current measurement circuits already present in the motor control system to measure coil resistance during startup, eliminating the need for separate dedicated diagnostic hardware. This resolves the contradiction by achieving precise detection without increasing overall system complexity.
3Productivity
If motor control instability is allowed to occur, then torque transmission through the reducer is maintained, but amplified torque abnormalities affect vehicle stability
Solution Approach 1:
The patent applies feedback by continuously monitoring motor operation parameters and using this information to detect coil abnormalities that could lead to unstable torque transmission. The system measures coil resistance and compares it against expected values, providing feedback about motor health status. When abnormalities are detected during startup or operation, the system can alert the driver or limit motor operation to prevent amplified torque variations from affecting vehicle stability through the high-ratio reducer.
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
Enables early detection and handling of motor coil abnormalities, enhancing the reliability of electric vehicles by identifying issues during non-traveling periods and ensuring quick countermeasures can be taken, thereby preventing potential travel-related problems.
Implementation Method 1
a coil resistance; and a determination block configured to determine the occurrence of the abnormality in the motor coil when the coil temperature is greater than a threshold value or when the coil resistance is greater than a threshold value
Implementation Method 2
an insulation resistance; and the determination block is configured to determine the occurrence of the abnormality in the motor coil when the coil temperature is greater than a threshold value or when the coil resistance or the insulation resistance is greater than a threshold value
Data Source
Figure 1
Figure 2
Figure 3~4(c)
AI summary
A diagnostic apparatus for diagnosing a drive motor of a vehicle includes a start-up abnormality detection section to detect coil temperature, coil resistance or insulation resistance of a motor coil during a non-traveling time in which electric power supply is applied and to determine occurrence of abnormality in the motor coil when the coil temperature is greater than a threshold value or the coil resistance or insulation resistance is greater than a threshold value, and a travel abnormality detection section to detect coil temperature, rotation number of the motor, a motor applied voltage and a motor current during traveling of the vehicle and to determine occurrence of abnormality in the motor coil when the coil temperature is greater than a threshold value or the relation between the motor applied voltage and the motor current relative to the rotation number fails to fall within a predetermined range.