Power Module Heat Sink Temperature Prediction Using Internal NTC Sensing
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Solution Overview
Problem
Conventional methods for predicting the junction temperature of silicon carbide (SiC) power modules using Negative Temperature Coefficient (NTC) sensors are inaccurate due to external temperature influences from coolant sensors, leading to potential overheating and burnout risks.
Innovation Solution
A method and apparatus that utilize an NTC sensor within the power module to predict heat sink temperature by estimating temperature variation based on power loss, thermal resistance, and coolant impedance, excluding external temperature effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is attached to the cooler to estimate coolant temperature, then the temperature measurement is obtained, but the measurement precision deteriorates due to external temperature influences
Solution Approach 1:
The patent extracts the temperature sensing function from the external cooler environment and relocates it inside the power module where the NTC sensor is already present. This removes the sensor from the harmful external temperature environment and eliminates the need for separate coolant temperature sensors, directly resolving the measurement precision issue caused by external temperature influences
Solution Approach 2:
The patent introduces a thermal model as an intermediary to bridge the gap between the NTC sensor temperature and the heat sink temperature. The thermal model uses power loss data and thermal resistance parameters to calculate the temperature difference, allowing accurate heat sink temperature prediction without direct external sensor measurement
2Device complexity
If an NTC sensor is used inside the power module, then the device complexity is reduced, but the measurement precision of junction temperature deteriorates without coolant temperature data
Solution Approach 1:
The patent makes the NTC sensor serve multiple functions: it simultaneously provides both the temperature compensation reference and the basis for calculating junction temperature through the thermal model. This multi-functionality eliminates the need for separate sensors while maintaining measurement precision
Solution Approach 2:
The patent implements a feedback mechanism where the NTC sensor continuously monitors temperature, and this information feeds into the thermal model along with power loss data. The model dynamically calculates and updates the junction temperature prediction, ensuring continuous accurate monitoring without additional sensors
3Quantity of substance
If external coolant sensors are used to measure temperature, then the temperature data is obtained, but the manufacturing cost and space requirements increase
Solution Approach 1:
The patent merges the temperature sensing function with the existing NTC sensor inside the power module, combining multiple functions into a single component. This eliminates the need for separate coolant temperature sensors, reducing both the quantity of components and the associated manufacturing costs and installation space
Solution Approach 2:
The patent enables the power module's internal NTC sensor to serve the dual purpose of both internal temperature monitoring and external heat sink temperature prediction. The module essentially measures its own temperature characteristics and uses this self-data for compensation, eliminating the need for external measurement devices
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
Accurately predicts heat sink temperature and junction temperature, reducing manufacturing costs and space requirements by eliminating external coolant sensors, while enhancing temperature management precision.
Implementation Method 1
a Negative Temperature Coefficient of Resistance (NTC) sensor is used inside the power module
Implementation Method 2
a heat sink located under a substrate on which a power module including at least one switching element and a Negative Temperature Coefficient of Resistance (NTC) sensor is attached
Data Source
AI summary
A method for predicting a temperature of a heat sink for cooling a power module including at least one switching element and a Negative Temperature Coefficient of Resistance (NTC) sensor is provided. The method for predicting a temperature of a heat sink includes: estimating a temperature variation of the NTC sensor using a power loss of the power module based on a power loss occurring in the at least one switching element according to driving of the power module and a thermal resistance of the power module; obtaining a temperature of the power module detected by the NTC sensor; and predicting the temperature of the heat sink from a difference between the temperature of the power module and the temperature variation of the NTC sensor.