Time-Based Junction Temperature Estimation in Power Modules
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Solution Overview
Problem
Existing methods for monitoring junction temperatures in power semiconductor devices are limited by the need for external sensors, high complexity, and cost, particularly when multiple temperature values need to be monitored.
Innovation Solution
A method and module for estimating junction temperatures in power semiconductor modules using duplicated pulse currents, an emulator circuit with tunable resistance and capacitance, and a comparator to measure voltage signal durations, converting these into estimated temperature values without the need for additional ADCs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple temperature values are monitored by duplicating the monitoring circuit, then the measurement capability is improved, but the device complexity and calibration effort are multiplied
Solution Approach 1:
The patent creates a universal monitoring circuit that can measure multiple temperature values by configuring the emulator circuit with different RC time constants. Instead of duplicating the entire monitoring circuit for each temperature threshold, a single circuit can be reconfigured to monitor multiple temperatures by changing the emulator's time constant, thereby reducing device complexity while maintaining multi-temperature monitoring capability.
Solution Approach 2:
The patent introduces dynamic reconfiguration capability to the monitoring circuit through tunable RC time constants in the emulator circuit. This allows the circuit to adapt its measurement range and sensitivity dynamically, enabling a single circuit to perform multiple temperature monitoring functions that would otherwise require multiple fixed circuits.
2Measurement precision
If the TSEP measurement is performed with an ADC, then the temperature estimation quality is improved, but the system cost increases
Solution Approach 1:
The patent replaces the ADC (analog-to-digital converter) with a time-based measurement approach using a comparator and timer. Instead of converting the analog TSEP signal to digital through an ADC, the system measures the time duration of the voltage signal, which is then converted to temperature. This substitution eliminates the need for expensive high-resolution ADCs while maintaining temperature measurement capability.
Solution Approach 2:
The patent changes the measurement parameter from voltage amplitude (requiring ADC) to time duration (measurable with simple timer). By measuring how long the voltage signal takes to reach a reference level rather than sampling the voltage value directly, the system achieves temperature estimation without requiring complex ADC hardware.
3Measurement precision
If the OTD circuit is made specific for each monitored device, then the measurement accuracy is improved, but the adaptability and calibration effort increase
Solution Approach 1:
The patent makes the OTD circuit dynamic and reconfigurable by introducing tunable RC time constants in the emulator circuit. This allows the same hardware circuit to be adapted to different devices and temperature ranges by adjusting the time constant, eliminating the need for dedicated fixed circuits for each device while maintaining measurement accuracy through proper calibration.
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 precise and cost-effective junction temperature estimation in power semiconductor modules, reducing calibration complexity and enabling dynamic adaptation of temperature estimation ranges and sensitivities.
Implementation Method 1
an emulator circuit comprising a resistance in series with a capacitor
Data Source
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AI summary
A measurement method for estimating junction temperatures of a power semi-conductor module (1) comprising: a. duplicating a pulse current; b. injecting simultaneously - a first duplicated pulse current to a control electrode (G) of a power transistor (TR) of said power semi-conductor module (1), and - a second duplicated pulse current to an emulator circuit (EMU) comprising a resistance (Remu) in series with a capacitor (Cemu); c. comparing a voltage signal (Vge) of said power transistor (TR) and a voltage signal (Vemu) of said emulator circuit (EMU) in such a way to generate a comparison signal (VCMP); d. in function of said comparison signal (VCMP), measuring duration (Δt) of said voltage signal (Vge) of said power transistor (TR) to reach the same value as said voltage signal (Vemu) of said emulator circuit (EMU); e. converting said measured duration (Δt) into an estimated value of a junction temperature (TJ).