Inverter Power Module Gate Oxide Self-Healing Through Junction Heating
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Solution Overview
Problem
Existing methods for restoring the gate oxide layer in power devices of inverter system controllers in electric vehicles are inefficient and can lead to increased power loss and premature device failure due to trapped charges, requiring frequent replacements.
Innovation Solution
A closed-loop power module gate oxide self-restoration control algorithm that maintains power switches at a predefined temperature for a predefined duration using a switch to directly connect the traction battery and electric machine windings, employing proportional integral controllers to manage junction temperatures and current, thereby removing trapped charges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing restoration methods are used for gate oxide layer, then restoration can be achieved, but power loss increases and device lifespan decreases due to trapped charges
Solution Approach 1:
The system uses the vehicle's own power switches and control algorithms to perform gate oxide restoration during normal operation. The controller monitors threshold voltage shifts and activates specific power switches to generate thermal energy that heals the gate oxide layer, eliminating the need for external restoration equipment and reducing power loss from trapped charges
Solution Approach 2:
The system changes the operating parameters of power switches dynamically. When gate oxide degradation is detected through threshold voltage monitoring, the controller adjusts switch operating conditions and activates restoration sequences that temporarily modify temperature and current parameters to facilitate oxide layer healing, thereby reducing power loss and extending device life
2Reliability
If power switches are maintained at predefined temperature for predefined period, then gate oxide layer is restored effectively, but additional control complexity is required
Solution Approach 1:
The controller implements a feedback mechanism that continuously monitors the threshold voltage of power switches. When degradation beyond a predetermined threshold is detected, the system automatically activates the restoration algorithm, which controls power switches to maintain predefined temperatures for specified durations. After restoration, the system verifies improvement through continued monitoring, creating a closed-loop control system that manages complexity through intelligent automation
Solution Approach 2:
The system performs preliminary monitoring of threshold voltage shifts during normal operation. When degradation is detected, restoration actions are activated in advance before catastrophic failure occurs. The controller pre-plans restoration sequences by selecting appropriate power switches and determining optimal temperature-time profiles based on the detected degradation level, thereby managing complexity through proactive rather than reactive control
3Temperature
If switch is closed to directly connect traction battery and electric machine windings, then junction temperature can be maintained for gate oxide healing, but current management becomes more complex
Solution Approach 1:
The system dynamically controls the closure and opening of switches based on real-time conditions. When gate oxide restoration is needed, the controller closes specific switches to create current paths that generate the required junction temperatures. The switch states are continuously adjusted during the restoration process to maintain optimal temperature profiles while managing current flow, demonstrating dynamic adaptation to achieve thermal healing without excessive 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
Effectively restores the threshold voltage of power switches to optimal levels, reducing power losses and extending the lifespan of the devices by maintaining junction temperatures at 120°C for 30 minutes to an hour, thus improving efficiency and reducing the need for replacements.
Implementation Method 1
A closed-loop power module gate oxide self-restoration control algorithm that maintains power switches at a predefined temperature for a predefined duration
Data Source
AI summary
A controller, while a vehicle is not being driven, closes a switch to directly connect windings of an electric machine with a center point of a traction battery, and operates an inverter system controller between the electric machine and traction battery to maintain switches of the inverter system controller at a predefined temperature for a predefined period.