Power Module Aging Detection via RF-Ultrasonic Reflectometry
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Solution Overview
Problem
Current methods for detecting aging-dictated damage or delamination in power modules of power electronic devices, such as converters, are unreliable due to the lack of long-term stability in radar systems and inaccuracies in thermal models and accelerated service life testing.
Innovation Solution
A method and apparatus that combine radiofrequency reflectometry with ultrasonic signal irradiation to detect damage or delamination in power modules. This involves scanning the power module with radiofrequency signals in the microwave or millimeter-wave range and measuring reflection signals, while also using ultrasonic signals to enhance detection sensitivity. The radiofrequency image representations generated from these signals are compared to identify changes indicative of damage or delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If radar systems are used for long-term monitoring of power modules, then aging detection capability is improved, but system stability deteriorates due to drift over time
Solution Approach 1:
The patent introduces an intermediary reference structure with known, stable electromagnetic properties that serves as a mediator between the radar system and the power module. This reference structure provides a stable reference signal that compensates for radar system drift, enabling reliable long-term aging detection without compromising system stability.
Solution Approach 2:
The patent creates a simplified copy or model of the power module's electromagnetic response using the reference structure. By comparing the actual power module measurements against this reference copy, the system can detect aging-related changes while compensating for radar system variations over time.
2Loss of time
If thermal models and accelerated service life testing are used to predict service life, then service life prediction capability is improved, but measurement precision deteriorates due to large errors in calculations
Solution Approach 1:
The patent replaces the mechanical/thermal modeling approach with an electromagnetic measurement-based approach. Instead of using thermal models and accelerated testing calculations, the system uses radar-based electromagnetic measurements to directly assess the physical state of the power module, providing more accurate service life predictions with reduced calculation errors.
3Measurement precision
If calibration devices are used to compensate for drift in RF network analyzers, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent implements a self-service calibration approach where the reference structure automatically provides drift compensation without requiring external calibration devices or complex recalibration procedures. The reference structure is inherently part of the measurement system and continuously compensates for drift, maintaining measurement accuracy while minimizing added complexity.
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 a reliable detection of aging-dictated damage or delamination in power modules, enabling accurate prediction of remaining operational service life without the need for complex drift correction in radar systems. It provides a higher measurement accuracy and dynamic range, suitable for long-term monitoring of power modules.
Implementation Method 1
scanning the power module with radiofrequency signals in the microwave or millimeter-wave range and measuring reflection signals
Implementation Method 2
using ultrasonic signals to enhance detection sensitivity
Data Source
AI summary
To facilitate a reliable detection of age-related damage or delamination on components the following is proposed: [i] within the scope of radiofrequency reflectometry, scanning a component by radiofrequency signal irradiation in the micrometer or millimeter wavelength range and by measuring at least one reflection signal, which was reflected at the component, in punctiform, one-dimensional or two-dimensional fashion for the purposes of generating at least one first radiofrequency image representation; [ii] scanning the component in direct time offset fashion with respect to the radiofrequency signal irradiation by a combination of ultrasonic signal irradiation and the radiofrequency signal irradiation in the micrometer or millimeter wavelength range and by measuring at least one further reflection signal, which was reflected at the component; and [iii] comparing the radiofrequency image representations generated based on the reflection signals, wherein determined changes in the radiofrequency image representations indicate damage or delamination on the component.