Power Semiconductor Aging Detection via Temperature-Independent Voltage
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Solution Overview
Problem
Existing electric drive systems face challenges in accurately determining the aging state of power semiconductor devices, which can lead to performance degradation and failure due to manufacturing tolerances, duty cycles, and environmental conditions, making it difficult to predict and detect failures effectively.
Innovation Solution
The method involves energizing the electric drive system to flow electrical current through power semiconductor devices and observing voltage levels, specifically at temperatures where voltage is independent of current, to determine the aging state by using a voltage sensing mechanism and a controller to compare measured values with reference values, providing a signal indicative of the aging state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage measurement is performed at arbitrary current levels, then measurement can be conducted at any operating point, but temperature variations cause voltage changes that mask aging effects reducing measurement precision
Solution Approach 1:
The patent changes the parameter of current level from arbitrary to specific predetermined levels where voltage becomes independent of temperature. By selecting operating points where the voltage-current relationship is temperature-independent, the measurement precision for aging detection is improved while eliminating temperature as a confounding variable.
Solution Approach 2:
The patent applies local quality by identifying specific regions in the voltage-current characteristic curve where temperature independence occurs. Instead of attempting to measure at all operating points, the solution focuses on localized measurement points where the voltage response to aging can be observed without temperature interference.
2Measurement precision
If existing voltage measurement methods are used without temperature compensation, then measurement simplicity is maintained, but temperature effects cause inaccurate aging determination
Solution Approach 1:
The patent changes the measurement parameter from general voltage at any current level to specific voltage levels at predetermined current levels where temperature independence is achieved. This parameter change allows accurate aging measurement without requiring complex temperature compensation circuits or algorithms.
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 accurate monitoring of power semiconductor device aging, enabling early detection of potential failures and predicting remaining service life, thereby extending the operational lifespan of electric drive systems.
Implementation Method 1
at current levels where a relationship between voltage and current level through the power semiconductor device is substantially independent of temperature
Data Source
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AI summary
Monitoring aging in an electric drive system includes energizing the electric drive system such that electrical current flows through a power semiconductor device therein, determining a value indicative of a voltage across the power semiconductor device, at a current level where voltage is substantially independent of temperature, comparing the determined value with a reference value, and outputting a signal responsive to a difference between the values that is indicative of an aging state of the power semiconductor device.