Power Semiconductor Temperature Estimation via Gate Resistor Voltage
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Solution Overview
Problem
Existing methods for monitoring temperature in power semiconductor modules face challenges such as difficulty in sensor placement, high complexity in acquisition systems, and inaccuracies due to temperature inhomogeneities within the module.
Innovation Solution
A measurement method that involves injecting a current from the emitter/source to the gate of the power semiconductor module, measuring the voltage across the current source, and comparing these measurements in reference and operational states to estimate temperature dispersion across the module.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individual gate access of power dies is used to measure individual gate resistances, then measurement precision is improved, but device complexity increases due to high number of external connections
Solution Approach 1:
The patent merges the temperature measurement function into the existing gate drive circuitry by utilizing the gate resistor already present in the power semiconductor device. Instead of requiring separate sensors or multiple external connections, the method measures the voltage across the existing gate resistor during normal operation, thereby combining measurement functionality with the existing circuit structure and reducing overall system complexity.
Solution Approach 2:
The power semiconductor device itself serves as the measurement object without requiring external sensors or additional components. The method uses the device's own electrical characteristics (gate voltage, gate resistor) during normal operation to self-diagnose temperature, eliminating the need for separate measurement systems and reducing external connection requirements.
2Measurement precision
If sensors are integrated inside the power module packaging, then measurement precision is improved, but ease of manufacture deteriorates as sensors must be initially planned during module conception and retrofitting is impossible
Solution Approach 1:
The method eliminates the need for separate temperature sensors by using the power semiconductor device's own electrical characteristics for temperature measurement. The gate resistor and gate voltage, which are already inherent parts of the device structure, serve dual purposes: normal operation and temperature sensing. This approach requires no additional components, sensors, or special manufacturing steps, thereby maintaining full manufacturing flexibility while achieving accurate temperature measurement.
3Ease of operation
If TSEP based methods are used for temperature estimation, then ease of operation is improved, but measurement precision deteriorates due to inaccuracies from temperature inhomogeneities
Solution Approach 1:
The patent addresses temperature inhomogeneities by measuring the voltage across the gate resistor at specific moments during the switching cycle when the device is most sensitive to temperature differences. By capturing the voltage waveform and analyzing it at critical points (such as during the Miller plateau or at specific time intervals), the method extracts temperature information that reflects local temperature variations rather than relying on averaged TSEP values, thereby improving precision while maintaining ease of operation.
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 allows for accurate estimation of temperature dispersion within power semiconductor modules without the need for individual access to semiconductor elements, thereby improving monitoring accuracy and reducing complexity.
Implementation Method 1
Many Temperature Sensitive Electrical Parameters (TSEP) based methods and in-chip sensors for on-line junction temperature estimation on power semiconductor are known
Data Source
AI summary
A measurement method for estimating temperatures of a MOS/MIS power semiconductor module comprising:in a reference statea. injecting a positive current Ig,ref to the gate, an initial voltage V0,ref of the gate-emitter/source, being superior to a flatband voltage Vfb,b. measuring the voltage Vig,ref(t) across the current source,c. stop the current injection Ig,ref when the voltage becomes inferior to the flatband voltage Vfb,in an operational stated. injecting a positive current Ig,op to the gate, an initial voltage V0,op of gate-emitter/source, being superior to a flatband voltage Vfb,e. measuring the voltage Vig,op(t) across the current source,f. stop the current injection Ig,op when the voltage becomes inferior to the flatband voltage Vfb,theng. comparing the measured voltages Vig,ref(t) and Vig,op(t),h. deducing, from the comparison, a temperature dispersion Tj,dev across the module.