Semiconductor Switch Thermal Fault Control for Vehicle Function Continuity
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Solution Overview
Problem
Existing vehicle control systems face challenges in maintaining operation continuity due to heat radiation failures in semiconductor switches, leading to potential safety and convenience issues, especially with increased thermal stress and integration of control functions in modern vehicles.
Innovation Solution
A vehicle control device that includes an operation control unit, actual temperature detection, temperature estimation, determination, and management units to detect and manage heat radiation failures, ensuring the operation continues even when heat radiation fails by adjusting power supply and limiting power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a temperature sensor outside the IPM is used to detect temperature before self-protection operates, then system protection becomes possible, but sudden function cutoff occurs impairing safety and convenience
Solution Approach 1:
The control device dynamically adjusts the threshold for reducing drive current based on the temperature difference between actual and estimated temperatures. When heat radiation failure is detected (large temperature difference), a lower threshold is applied, allowing the system to respond gradually rather than with sudden cutoff, thus maintaining vehicle function continuity while still providing protection.
Solution Approach 2:
The system changes the protection parameter (threshold value) based on the detected heat radiation failure condition. By adjusting the threshold dynamically according to the temperature discrepancy, the system transitions from a fixed-threshold protection mechanism to an adaptive one, preventing sudden function cutoff while maintaining reliability.
2Adaptability or versatility
If control functions and power supply function are integrated to increase vehicle functions, then more operations are available, but heat radiation failure becomes more frequent due to increased thermal stress
Solution Approach 1:
The system performs preliminary detection of heat radiation failure by comparing actual temperature with estimated temperature before overtemperature occurs. By detecting the anomaly early through temperature discrepancy analysis, the system can take preventive measures (reducing drive current) before heat radiation failure causes sudden function cutoff, thus maintaining reliability despite increased thermal stress from integration.
3Temperature
If drive current is reduced when temperature exceeds threshold, then overtemperature is prevented, but control target operation is interrupted
Solution Approach 1:
The system dynamically adjusts the drive current reduction based on the temperature difference and threshold settings. When heat radiation failure is detected, the threshold is set to allow gradual current reduction rather than immediate cutoff, enabling the control target to continue operating at reduced capacity while still preventing overtemperature, thus maintaining operation continuity.
Data Source
AI summary
A controller includes: a semiconductor switch that controls an operation of a control target to which electric power is supplied from a battery; a temperature detection element that detects an internal temperature of the semiconductor switch as an actual temperature; a temperature estimation unit that estimates the internal temperature as an estimated temperature based on current supplied to the semiconductor switch; a determination unit that outputs a determination result determining heat radiation failure of the semiconductor switch based on a temperature difference between the actual temperature and the estimated temperature; and a drive management unit that manages the operation of the semiconductor switch such that the actual temperature is less than an overtemperature threshold and continues the operation of the semiconductor switch when the determination result that the semiconductor switch has the heat radiation failure is obtained.