Heater Power Control for Ceramic Substrate Thermal Stress
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Solution Overview
Problem
Heaters with resistive elements experience non-uniform heating due to manufacturing differences and position relative to heat sinks, leading to thermal stress and potential thermal cracks in ceramic substrates.
Innovation Solution
A control system comprising a power converter, sensor circuit, and controller that adjusts voltage output to heating elements based on measured electrical characteristics and temperature differences, using a reference temperature sensor to manage power distribution and reduce thermal stress across heating zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the same power is applied to all resistive heating elements during heater startup, then the heater startup process is simple and fast, but non-uniform heating occurs leading to thermal stress and potential thermal cracks in the ceramic substrate
Solution Approach 1:
The patent applies different power levels to different heating zones based on their individual heating rates and thermal characteristics. Each heating zone is independently controlled with customized power parameters to achieve uniform temperature distribution across the heater, preventing thermal stress and ceramic substrate damage while maintaining efficient startup performance
2Reliability
If different power levels are applied to different heating zones to achieve uniform heating, then thermal stress and ceramic substrate damage are reduced, but the control system complexity increases
Solution Approach 1:
The heater is divided into multiple independently controllable heating zones, each with its own power control parameters. This segmentation allows localized temperature management to prevent thermal stress, while the modular zone structure makes the control system manageable through discrete, independent control channels rather than a monolithic complex system
Solution Approach 2:
The control system uses temperature sensors to monitor each heating zone and implements feedback control to dynamically adjust power levels. This feedback mechanism automates the complex control decisions, reducing the burden on operators and making the sophisticated temperature management system more manageable and reliable
3Reliability
If monitoring and control mechanisms are implemented to prevent thermal stress, then ceramic substrate reliability is improved, but the device complexity and cost increase
Solution Approach 1:
The control system automatically monitors temperature and adjusts power levels without requiring external intervention or complex manual monitoring. The system self-regulates each heating zone based on real-time temperature feedback, providing reliable thermal stress prevention through automated control rather than complex manual monitoring systems
Solution Approach 2:
The system dynamically changes power parameters (voltage, current, duty cycle) based on real-time temperature measurements and predefined thermal models. This parameter adaptation allows the system to prevent thermal stress through intelligent control algorithms rather than requiring complex physical monitoring infrastructure
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
The system effectively reduces thermal stress and prevents thermal cracks by dynamically adjusting power to heating elements, ensuring uniform heating and extending the lifespan of ceramic substrates.
Implementation Method 1
a heating plate that has a ceramic substrate and a plurality of resistive heating elements embedded in the ceramic substrate
Implementation Method 2
The reference temperature sensor is one of an infrared camera, a thermocouple, and a resistance temperature detector
Data Source
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AI summary
The present disclosure is directed toward a method of controlling a heater, the method comprising: controlling power to a heater based on a first state model of a control program, wherein the control program is defined by at least two state models and the at least two state models includes the first state model; determining, by the control program, whether a transition condition for the first state model is satisfied, wherein each of the at least two state models defines a transition condition and a subsequent state model to be performed when the transition condition is met; and controlling, by the control program, power to the heater based on a second state model in response to the transition condition of the first state model being satisfied, wherein the second state model is among the at least two state models and is provided as the subsequent state model of the first state model.