Power Converter Lifetime Estimation Using the Most Stressed Module
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Solution Overview
Problem
Existing methods for estimating the remaining lifetime of electronic power converters, such as amplifiers, are computationally intensive and do not account for the thermal cycling effects in devices with fast varying load profiles, and lack solutions for refurbishment through power module replacement.
Innovation Solution
A method to estimate the accumulated fatigue damage of a switching power converter by identifying the thermally most heavily stressed power module, measuring its reference temperature and current, and calculating fatigue damage based on these parameters, reducing computational effort while maintaining accuracy, and enabling refurbishment through stored lifetime data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If switch junction temperature is determined for each controlled switch, then lifetime estimation accuracy is improved, but processing load increases significantly
Solution Approach 1:
The patent extracts only the critical parameter (maximum junction temperature among all switches) needed for lifetime estimation, rather than processing all switch temperatures. This is achieved by identifying the switch with the highest junction temperature and using only that value for the lifetime calculation, thereby reducing processing load while maintaining estimation accuracy.
Solution Approach 2:
The patent applies partial action by calculating lifetime based on a single representative switch (the one with maximum temperature) rather than all switches. This partial approach is sufficient because the lifetime of the power converter is determined by its most stressed component, making full calculation of all switches unnecessary.
2Device complexity
If high-level lifetime models are used for constant power usage, then estimation is simplified, but accuracy deteriorates for fast varying load profiles
Solution Approach 1:
The patent changes the approach from using complex models for all switches to using a simplified model based on a single critical parameter (maximum junction temperature). By focusing on the most stressed switch and using its temperature for lifetime estimation, the patent achieves accurate results for fast varying load profiles while keeping the model simple.
3Reliability
If lifetime estimation is performed for all power modules, then comprehensive assessment is improved, but processing effort increases
Solution Approach 1:
The patent extracts only the critical power module (the one containing the switch with maximum junction temperature) for detailed lifetime assessment. This extraction approach provides comprehensive assessment of the system's reliability while avoiding unnecessary processing of non-critical modules, thereby maintaining processing efficiency.
Data Source
AI summary
A method is disclosed for estimating an accumulated fatigue damage of a switching power converter. The switching power converter has power modules each including a first semiconductor device. The method includes determining of the plurality of power modules, a single power module having the first semiconductor device being thermally most heavily stressed. During operation of the switching power converter, a reference temperature is measured related to a temperature of at least the single power module. A current of the switching power converter is determined, particularly a current representative of a power dissipation through the first semiconductor device. A single fatigue damage of the first semiconductor device of the single power module is calculated based at least on the current and the reference temperature. A switching power converter may have a processing unit configured to implement the above method.