Surface Temperature Estimation Using Thermal Transfer Functions
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Solution Overview
Problem
Existing electronic apparatuses face challenges in accurately estimating surface temperatures due to shape constraints, which affect cooling capabilities, leading to potential overheating, especially when temperature sensors are closely located to heat sources, thereby deteriorating estimation accuracy.
Innovation Solution
An electronic apparatus that includes a housing, a substrate with components, reference and temperature sensors, and a processor that estimates outside air temperature using thermal resistance and time constant-based transfer functions to accurately calculate surface temperature, considering the impact of heat sources on the reference temperature sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If temperature sensors are arranged close to heat sources to improve temperature measurement capability, then temperature measurement capability is improved, but estimation accuracy deteriorates due to heat source influence on the reference temperature sensor
Solution Approach 1:
The patent divides the temperature sensing function into two independent parts: a reference temperature sensor that measures only the baseline temperature (不受热源影响) and individual temperature sensors that measure temperatures near heat sources. This segmentation allows the reference sensor to remain accurate while enabling temperature monitoring close to heat sources, resolving the contradiction between measurement capability and estimation accuracy.
Solution Approach 2:
The reference temperature sensor acts as an intermediary that provides baseline temperature data, which is then combined with measurements from individual temperature sensors through thermal resistance and time constant calculations. This intermediary approach allows the system to compensate for heat source influence and accurately estimate surface temperatures without requiring the reference sensor to be far from heat sources.
2Shape
If the housing shape is constrained to meet design requirements, then design flexibility is improved, but cooling capability deteriorates leading to insufficient heat dissipation
Solution Approach 1:
The patent performs preliminary thermal characterization by measuring thermal resistances and time constants between various components, temperature sensors, and the housing surface before actual operation. This preliminary data is stored and used during operation to predict surface temperatures without requiring physical temperature sensors on the housing surface, thus maintaining design flexibility while enabling effective thermal management.
3Temperature
If surface temperature is reduced by limiting component operation level, then surface temperature is improved, but productivity deteriorates due to decreased operation speed
Solution Approach 1:
The patent implements a feedback control system that continuously monitors temperatures from individual temperature sensors and reference temperature sensors, calculates predicted surface temperatures using thermal models, and adjusts component operation levels based on these predictions. This feedback mechanism allows the system to maintain optimal performance by reducing operation levels only when and where necessary to prevent excessive surface temperatures, rather than applying blanket limitations that would reduce overall productivity.
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 solution enables accurate surface temperature estimation and effective cooling control by accounting for the heat source's influence on the reference temperature sensor, improving estimation accuracy even in compact designs where sensors are closely positioned to heat sources.
Implementation Method 1
a temperature sensor that measures a temperature based on heat transfer from the heat source
Implementation Method 2
the heat could be transferred from the component to the surface of the housing of the electronic apparatus
Implementation Method 3
a transfer function representing heat transfer from the heat source to the surface of the housing
Data Source
AI summary
An electronic apparatus includes a housing, a substrate in the housing, components on the substrate, a reference temperature sensor, temperature sensors for the respective components, and an arithmetic processing unit. The arithmetic processing unit estimates an outside air temperature by using a reference temperature, temperatures acquired by the temperature sensors, first transfer functions, second transfer functions, and third transfer functions, and estimates a surface temperature of the housing based on the outside air temperature. Each first transfer function is defined based on a thermal resistance and a thermal time constant from a component to the reference temperature sensor. Each second transfer function is defined based on a thermal resistance and a thermal time constant from a component to an individual temperature sensor. Each third transfer function is defined based on a thermal resistance and a thermal time constant from a component to a surface of the housing.