Power Semiconductor Module Deterioration Detection via Thermal Model
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Solution Overview
Problem
Power semiconductor modules face premature failure due to thermomechanical fatigue, leading to inaccurate lifetime predictions, as existing methods struggle to reliably detect transient temperatures and account for component deterioration.
Innovation Solution
A method involving the creation of a thermal model to determine a reference temperature, measuring temperature-sensitive electrical parameters, and calculating a temperature difference to assess deterioration, allowing for accurate prediction of remaining lifetime and enabling temperature-dependent power regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermistors are soldered to the substrate to monitor temperature, then temperature monitoring is enabled, but the spatial separation from power semiconductor components reduces measurement precision of transient temperatures
Solution Approach 1:
The patent uses temperature-sensitive electrical parameters (TSEPs) of the power semiconductor components themselves as intermediaries to infer temperature. Instead of directly measuring temperature with thermistors, the method measures electrical parameters (like forward voltage of diodes or threshold voltage of MOSFETs) that are sensitive to temperature changes, thereby eliminating the need for physical temperature sensors near the components.
Solution Approach 2:
The patent replaces the mechanical/physical temperature sensing system (thermistors) with an electrical measurement system. By substituting direct thermal measurement with electrical parameter measurement, the system achieves both higher measurement precision and eliminates the spatial separation issue inherent in physical sensor placement.
2Measurement precision
If equivalent thermal networks are used to calculate temperature from power losses, then temperature can be determined indirectly, but deterioration of power semiconductor components is not accounted for
Solution Approach 1:
The patent transitions from a static thermal network model to a dynamic assessment method. Instead of relying on fixed thermal resistance values and steady-state power loss calculations, the method continuously monitors temperature-sensitive electrical parameters during operation, capturing the dynamic behavior and deterioration of the power semiconductor components over time.
Solution Approach 2:
The patent introduces feedback by continuously measuring temperature-sensitive electrical parameters and using these measurements to assess both current temperature and component deterioration. The measured electrical parameters provide real-time feedback about the component's health status, enabling the system to detect deviations from normal operation that indicate deterioration.
3Duration of action of moving object
If lifetime calculations are based on predetermined load profiles and temperature monitoring, then lifetime prediction can be performed, but accurate transient temperature detection is inhibited
Solution Approach 1:
The patent enables the power semiconductor components to self-report their temperature status through their own electrical parameters. The components' inherent electrical characteristics (such as voltage drops and threshold voltages) serve as built-in temperature sensors, eliminating the need for separate temperature monitoring infrastructure and enabling accurate transient temperature detection for lifetime calculations.
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
This approach allows for reliable determination of power semiconductor module deterioration and accurate prediction of remaining lifetime, preventing premature failure and ensuring efficient operation by accounting for thermal changes and component wear.
Implementation Method 1
measuring at least one temperature-sensitive electrical parameter (TSEP) of the power semiconductor module (1) at at least one later point in time compared to the reference time point
Implementation Method 2
for creation of the thermal model (4), a thermal impedance of the power semiconductor module (1) describing a thermal path of the power semiconductor module (1) is determined
Implementation Method 3
a thermal impedance of the power semiconductor module (1) describing a thermal path of the power semiconductor module (1) is determined
Implementation Method 4
The electrical losses of the IGBTs and of the diodes can be calculated from current and voltage measurements
Data Source
AI summary
The present disclosure relates to power semiconductor modules. The teachings thereof may be embodied in modules with a power semiconductor component and methods, as well as a circuit arrangement. For example, a method may include: developing a thermal model of the power semiconductor module at a reference time point; establishing a reference temperature based on the thermal model; measuring a temperature-sensitive electrical parameter of the power semiconductor module during operation of the power semiconductor module; determining a current temperature from the measured temperature-sensitive electrical parameter of the power semiconductor module; calculating a temperature difference between the current temperature and the reference temperature; and determining a deterioration of the power semiconductor module based on the calculated temperature difference.