EV Motor Temperature Warning Thresholds for Torque Limitation
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Solution Overview
Problem
Existing technologies fail to adequately manage the period between alerting the driver and limiting the motor torque in electrified vehicles, particularly when the motor temperature rises rapidly.
Innovation Solution
An electrified vehicle control device that includes an acquisition unit to monitor motor temperature and an index of temperature rise, an execution unit to notify the driver of an alert when the temperature exceeds a first threshold, and a limitation unit to limit motor torque when the temperature reaches a second threshold, with the first threshold adjusted based on factors like road slope and coolant temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the torque of the motor is limited when the temperature reaches the second temperature threshold, then the temperature rise is suppressed, but the period from alert to driver response becomes insufficient when temperature rises rapidly
Solution Approach 1:
The system performs preliminary action by notifying the driver at a first temperature threshold before the motor temperature reaches the second threshold where torque limitation occurs. This advance notification gives the driver time to take corrective measures (such as reducing load or improving cooling) before torque limitation becomes necessary, thus preventing excessive temperature rise while providing sufficient response time.
2Device complexity
If a fixed temperature threshold is used for torque limitation, then the control logic is simple, but the system cannot adapt to different operating conditions such as road slope and coolant temperature
Solution Approach 1:
The system applies dynamics by making the first temperature threshold dynamic rather than fixed. The threshold is adjusted based on real-time operating conditions including road slope and coolant temperature. When the vehicle is on an ascending slope or coolant temperature is high, the first threshold is set lower to provide earlier warning. This dynamic adjustment maintains simple control logic while significantly improving adaptability to various operating conditions.
Data Source
AI summary
A control device for an electrified vehicle includes: an acquisition unit for acquiring a temperature of a motor which is a driving power source of an electrified vehicle and an index value indicating ease of temperature rise of the motor; an execution unit that executes a notification process for notifying a driver of electrified vehicle of a warning when a temperature of the motor is equal to or higher than a first temperature and lower than a second temperature; a limitation unit that limits a torque of the motor when a temperature of the motor is equal to or higher than the second temperature; and a setting unit that sets the first temperature to a lower temperature than a temperature when the index value is equal to or higher than a threshold value when the index value is equal to or higher than the threshold value.