Power Semiconductor Switch Resistance Sensing for Temperature Calibration
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Solution Overview
Problem
Existing methods for determining the temperature dependency of forward resistance in power semiconductor modules are complex, costly, and require additional components, which can lead to inaccurate temperature measurements due to spatial separation from the power semiconductor.
Innovation Solution
A device comprising a pulse unit to send current pulses to the switch, a measurement unit to measure the resistance during and/or after the pulse, and an evaluation unit to determine the resistance/temperature curve using a predefined prediction model, allowing for indirect temperature measurement without external sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional temperature measurement components (NTC/PTC thermistors) are integrated into the power semiconductor module, then temperature monitoring capability is improved, but device complexity and space requirements increase
Solution Approach 1:
The power semiconductor switch itself serves as the temperature sensor by utilizing its inherent forward resistance temperature dependency. The switch monitors its own temperature through resistance measurements during normal operation, eliminating the need for separate temperature sensing components and achieving self-diagnostics capability
Solution Approach 2:
The power semiconductor switch performs dual functions: power switching operation and temperature sensing. The same component that conducts power current also provides temperature information through its resistance characteristics, reducing overall device complexity while maintaining measurement capability
2Ease of manufacture
If additional temperature measurement components are spatially separated from the power semiconductor, then manufacturing simplicity is improved, but measurement accuracy deteriorates due to temperature gradient differences
Solution Approach 1:
The power semiconductor switch measures its own temperature directly at its actual location, eliminating spatial separation issues. By using the switch's intrinsic resistance temperature dependency, the measurement occurs exactly where needed without requiring proximity to external sensors, ensuring accurate representation of the switch's thermal state
3Measurement precision
If calibration is performed for each power semiconductor to account for production process variations, then measurement reliability is improved, but manufacturing cost and time increase
Solution Approach 1:
A resistance/temperature characteristic curve is determined during the manufacturing process for each power semiconductor switch. This preliminary characterization captures individual device variations and stores the data for later use, enabling accurate temperature measurements without requiring complex real-time calibration procedures during operation
Solution Approach 2:
The actual temperature measurement is performed by referencing the pre-determined resistance/temperature characteristic curve specific to each device. Instead of performing complex calibration measurements during operation, the system uses the stored characteristic copy to translate resistance measurements into accurate temperature readings, simplifying the operational process
4Reliability
If complex calibration procedures are implemented to account for aging effects, then long-term measurement reliability is improved, but system complexity increases
Solution Approach 1:
The resistance/temperature characteristic curve is determined once during manufacturing and stored for the device's entire service life. This preliminary action accounts for the device's initial state and aging behavior, eliminating the need for continuous complex calibration procedures while maintaining measurement reliability throughout the power semiconductor's operational lifetime
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 method simplifies the calibration process, reduces costs, and provides reliable temperature measurements over the service life of the power semiconductor module, enabling efficient and precise temperature monitoring without the need for additional hardware.
Implementation Method 1
A current pulse is conducted through the switch, causing it to heat up
Implementation Method 2
the resistance of the switch can be determined on the basis of a voltage drop during the current pulse or after the current pulse
Implementation Method 3
The temperature can be measured on the basis of the temperature dependency of the resistance
Data Source
AI summary
A device for determining temperature dependency of a forward resistance in a switch in a power semiconductor module, includes a pulse unit for sending a current pulse to the switch, a measurement unit for measuring the resistance in the switch during a measurement period while and/or after the current pulse has been sent to the switch, and an evaluation unit for determining a resistance/temperature curve for the switch based on the measured resistance and a predefined prediction model.