Parallel Power Module Control for Balanced Thermal Degradation

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Solution Overview

Problem

Heterogeneous power dies or modules connected in parallel experience varying degradation rates and modes due to electro-thermo-mechanical differences, leading to reliability and robustness issues, and existing methods fail to effectively balance degradation for improved performance and lifetime.

Innovation Solution

A method and device that monitor and control the temperature cycles of each power die or module to determine reliability parameters, allowing for continuous equilibration of degradation levels by adjusting temperature references based on calculated stress inputs and damage change rates, thereby minimizing differences in degradation levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If heterogeneous power dies or modules are connected in parallel to improve performance such as efficiency, then power and energy utilization is improved, but reliability and robustness deteriorate due to electro-thermo-mechanical differences leading to unbalancing and varying degradation rates

Engineering Contradiction:
ImproveefficiencyVSAvoidreliability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the switching patterns of parallel power modules based on real-time monitoring of temperature, voltage, and current parameters. The control system modifies operational parameters (switching times, duty cycles) to compensate for electro-thermo-mechanical differences between heterogeneous modules, thereby maintaining both high efficiency and improved reliability through adaptive parameter optimization.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If sorting is performed during manufacturing to equalize electro-thermo-mechanical characteristics of parallel power dies, then reliability is improved by equalizing degradation rates, but device complexity and manufacturing cost increase

Engineering Contradiction:
ImprovereliabilityVSAvoidsorting process
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements self-service by enabling power modules to self-monitor their own electro-thermo-mechanical characteristics through integrated sensors and control circuits. Each module autonomously measures its temperature, voltage, and current parameters, and the control system automatically adjusts switching patterns based on this self-reported data, eliminating the need for external sorting processes while maintaining equalized degradation rates and high reliability.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If pre-characterization of electro-thermal performances is performed to determine switching patterns, then initial performance balancing is achieved, but the approach becomes obsolete when temperature evolves or degradation appears, leading to increased cost and reduced performance

Engineering Contradiction:
Improveswitching pattern determinationVSAvoidperformance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies feedback by implementing a closed-loop control system that continuously monitors temperature, voltage, and current parameters of parallel power modules in real-time. The control system uses this feedback information to dynamically adjust switching patterns, ensuring that the system adapts to temperature evolution and degradation over time. This continuous feedback mechanism replaces obsolete pre-characterization approaches, maintaining optimal performance and reliability throughout the operational lifetime of the power modules.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4099032B1A method and a device for increasing the lifetime of power dies or power modules
Publication Date: 2023.12.20 MITSUBISHI ELECTRIC R&D CENTRE EUROPE BV
  • EP4099032B1 patent drawingFigure 1a
  • EP4099032B1 patent drawingFigure 1b
  • EP4099032B1 patent drawingFigure 1c

AI summary

The present invention concerns a method and a system for increasing the lifetime of at least two power dies or power modules. The invention: - senses the temperature of the power dies or the power modules, - identifies, for each power die or power module, temperature cycles from the sensed temperatures, - determines, for each power die or power module, reliability parameters from the identified temperature cycles, - determines, for each power die or power module, reference temperatures, - subtracts, for each power die or power module, the sensed temperature of the power die or power module from the determined reference temperature of the power die or power module, - adjusts the duration of the conducting time and/or the switching delay of at least one power die or power module according to the sign of the output of the subtraction.