Adaptive Heater Power Limiting for Temperature Trajectory Control
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Solution Overview
Problem
Existing temperature control technologies for heated bodies, such as reflow furnaces and thermostatic baths, face challenges in achieving a desired temperature trajectory due to mismatched power ratings and lack of consideration for temperature change over time, leading to issues like integration windup and overshoot.
Innovation Solution
A temperature control device and method that sets a target temperature and change rate, adjusts the upper limit power value based on actual measured change rates, and updates the power limit to maintain the desired temperature trajectory, using a target setting part, upper limit value setting part, heating processing part, and determination part to ensure the temperature follows the desired path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the upper limit value of operation amount is set to avoid integration windup, then reliability is improved, but the temperature cannot reach the desired trajectory
Solution Approach 1:
The patent applies dynamics by making the upper limit value of the operation amount adjustable and adaptive rather than fixed. The control device dynamically changes the upper limit value based on the current temperature and temperature change rate, allowing the system to optimize between avoiding integration windup and achieving desired temperature trajectory at different stages of the heating process.
Solution Approach 2:
The patent implements parameter changes by modifying the upper limit value of the operation amount based on temperature and temperature change rate conditions. The control device adjusts this parameter in real-time according to the current state of the heated body, enabling the system to adapt to different heating phases and maintain optimal control performance.
2Ease of operation
If the upper limit value of heating power is determined based on air temperature difference, then ease of operation is improved, but the temperature trajectory cannot be controlled accurately
Solution Approach 1:
The patent applies parameter changes by using multiple parameters (temperature and temperature change rate) instead of a single parameter (air temperature difference) to determine the upper limit value. This multi-parameter approach enables more accurate control of the temperature trajectory while maintaining automatic operation.
Solution Approach 2:
The patent implements feedback by continuously monitoring the actual temperature and temperature change rate, then using this information to adjust the upper limit value of the operation amount. This closed-loop feedback mechanism ensures that the temperature trajectory is accurately controlled while the system operates automatically.
3Device complexity
If a single heater with large power rating is used for different heated bodies, then device complexity is reduced, but the temperature trajectory control becomes difficult
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the upper limit value of the operation amount based on the specific heated body's characteristics, target temperature, and current temperature change rate. This allows a single heater to effectively control different heated bodies with varying heat capacities by changing control parameters rather than hardware configuration.
Solution Approach 2:
The patent implements dynamics by making the control system adaptive to different heated bodies through real-time adjustment of the upper limit value. The system dynamically responds to the specific thermal characteristics of each heated body, enabling accurate temperature trajectory control with a universal heater configuration.
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 solution effectively controls the temperature of a heated body to be close to the desired trajectory, reducing overshoot and windup by dynamically adjusting the power limit in real-time based on actual temperature changes.
Implementation Method 1
a heating system heating the heated body using a heating body
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
Realized is a temperature control device that can control the temperature of a body-to-be-heated, in a state close to a desired temperature locus. A temperature control device (100) comprises: an operation amount upper limit setting part (121) that sets an upper limit of an operation amount of a heater (20); and a temperature change rate comparing part (119) that determines, in every prescribed time period, whether an actual measured change rate of the temperature of a body-to-be-heated with respect to time is outside a prescribed range that includes a target rate of change. The operation amount upper limit setting part (121) sets the upper limit to a preset initial value when operation of the heater (20) is started toward the target temperature, and updates the upper limit, in a period until the temperature of the body-to-be-heated reaches the target temperature, such that the difference between an actual measured temperature and a temperature locus that is represented using the target rate of change becomes smaller when it is determined that the actual measured change rate is outside the prescribed range.