Power Semiconductor Lifetime Prediction Under Variable Thermal Stress

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Solution Overview

Problem

Predicting the lifetime of power semiconductor devices under variable thermal amplitude stress is challenging due to numerous influencing factors and manufacturing differences, with existing methods lacking a straightforward approach to estimate remaining useful lifetime based on actual or typical load conditions.

Innovation Solution

A method involving data collection on working conditions, calculation of switching frequency and Key Performance Indicators, implementation of these indicators into a Machine Learning model, and estimation of total switching cycles throughout the device's lifetime, utilizing parameters such as temperature differences, switching cycles, and heating/cooling rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional lifetime prediction methods are used, then manufacturing simplicity is maintained, but prediction accuracy deteriorates due to inability to account for variable thermal amplitude stress and actual load conditions

Engineering Contradiction:
Improvelifetime prediction accuracyVSAvoidprediction method complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent transforms lifetime prediction from a static manufacturer-provided value to a dynamic estimation by changing key parameters: actual load conditions, temperature swings, and switching frequencies are continuously monitored and fed into the machine learning model to adjust predictions in real-time, accounting for variable thermal amplitude stress

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces traditional mechanical/empirical lifetime prediction methods with a machine learning-based system that uses computational algorithms to analyze operational data and predict remaining useful life, substituting physical testing and estimation with intelligent data processing

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If manufacturer general plots and histograms are used, then ease of operation is maintained, but reliability deteriorates due to inability to estimate lifetime under variable thermal conditions

Engineering Contradiction:
Improvelifetime estimation reliabilityVSAvoidlifetime prediction simplicity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system enables devices to self-monitor their own operational parameters (temperature, load, switching frequency) and self-predict their remaining lifetime through the integrated machine learning model, eliminating the need for external manufacturer consultations or complex manual calculations

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent implements continuous feedback loops where operational data from temperature sensors and load monitors are fed back to the machine learning model, which continuously refines lifetime predictions based on actual device performance and environmental conditions

Inventive Principle:
Principle #23Feedback

3Measurement precision

If detailed monitoring of temperature swings and switching cycles is implemented, then prediction accuracy is improved, but device complexity increases due to multiple sensors and data processing requirements

Engineering Contradiction:
Improveoperational parameter measurement accuracyVSAvoidmonitoring system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent designs the monitoring system to serve multiple functions simultaneously: temperature sensors monitor both thermal conditions for immediate cooling control and accumulate data for lifetime prediction, while switching frequency measurement serves both operational control and wear assessment, reducing overall system complexity through multi-functional components

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines multiple monitoring functions (temperature monitoring, load monitoring, switching frequency measurement) and data processing (histogram creation, thermal cycle counting) into a unified machine learning-based prediction system, merging previously separate functions into an integrated intelligent platform

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4417984A1A method for predicting a lifetime of a power semiconductor device
Publication Date: 2024.08.21 ABB (SCHWEIZ) AG
  • EP4417984A1 patent drawingFigure 1
  • EP4417984A1 patent drawingFigure 2
  • EP4417984A1 patent drawingFigure 3

AI summary

The present disclosure relates to methods of predicting lifetime of a power semiconductor device. According to the invention there is provided a method for predicting a lifetime of a power semiconductor device comprising of: a) obtaining data related to working conditions of the power semiconductor device; b) calculating a switching frequency with its peaks in switching cycle on a basis of obtained data; c) calculating at least one KPI, Key Performance Indicators; d) implementing received KPIs and an at least one input feature to Machine Learning model; e) estimating lifetime of the power semiconductor device by receiving total number of switching cycles that the power semiconductor device is able to perform throughout its lifetime.