PTC Heater Control Device for Fine Output Power Regulation
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Solution Overview
Problem
Conventional PTC heater control devices can only supply power in a stepwise manner, making fine control of output power values impossible due to the inability to output intermediate power values defined by combination patterns of ON and OFF states of switching elements.
Innovation Solution
A heater control device with switching means and ratio controlling means that adjusts the ON/OFF ratio of PTC elements based on ON time to OFF time to match required power values, allowing for fine control of output power by controlling the energized and non-energized states of PTC elements, and includes a feedback mechanism to correct power errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If switching elements are controlled based on predefined combination patterns, then the control structure remains simple, but the output power can only be adjusted in steps and cannot achieve fine control
Solution Approach 1:
The patent applies dynamics by transitioning from static predefined combination patterns to dynamic real-time control. The control device calculates the required power ratio and dynamically adjusts the ON/OFF timing of switching elements based on the actual required power level, enabling continuous fine control of output power while maintaining a relatively simple control structure through algorithmic optimization.
Solution Approach 2:
The patent changes the control parameter from discrete combination patterns to continuous time-ratio parameters. By controlling the ratio of ON time to OFF time of switching elements based on the required power level, the system achieves continuous adjustment of output power in fine steps rather than being limited to predetermined discrete levels.
2Speed
If the switching period is shortened to improve response speed, then the system can respond faster to power changes, but switching loss increases
Solution Approach 1:
The patent optimizes the switching period parameter by establishing a specific relationship between the switching period and the charging/discharging characteristics of the capacitor. By setting the switching period to be longer than the charging/discharging time constant, the system achieves fast response while minimizing switching losses through reduced frequency of switching operations.
Solution Approach 2:
The patent employs periodic action by using controlled switching cycles where the switching elements are turned ON and OFF in periodic intervals. The periodic switching is optimized based on the capacitor's charging and discharging characteristics, allowing the system to maintain smooth power delivery while reducing the total number of switching events and associated losses.
3Loss of energy
If the switching period is lengthened to reduce switching loss, then energy efficiency improves, but the temperature control precision deteriorates
Solution Approach 1:
The patent implements feedback control by continuously monitoring the actual power output and comparing it with the required power level. Based on this feedback, the control device adjusts the switching timing and ratio to maintain precise temperature control. The feedback mechanism ensures that even with longer switching periods, the system can correct any deviations and maintain accurate temperature regulation.
Solution Approach 2:
The patent applies dynamics by making the switching timing adaptive rather than fixed. The control device dynamically adjusts the ON/OFF timing based on real-time power requirements and feedback, allowing the system to maintain precise temperature control while operating with longer switching periods that reduce switching losses.
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
Enables precise and accurate control of output power values, improving efficiency by minimizing switching loss and maintaining temperature differences within predetermined limits, while preventing excessive current surges and reducing power consumption variations.
Implementation Method 1
heat is generated by energizing a PTC element which is a resistive element having a positive temperature coefficient
Implementation Method 2
PTC element which is a resistive element having a positive temperature coefficient
Implementation Method 3
switching means which are provided so as to correspond to the PTC heaters and which switch between an energized state and a non-energized state of the PTC elements by being turned ON and OFF
Implementation Method 4
controls a ratio of the energized state to the non-energized state of the PTC elements based on a ratio of ON time to OFF time for which an average power within a certain period matches the required power
Data Source
Figure 1
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Figure 4
AI summary
The present invention controls output power values finely and accurately. A heater control device to be applied to a heater unit which has at least two PTC heaters having PTC elements includes switching units which are provided so as to correspond to the PTC heaters and which switch an energized stat and a non-energized state of the PTC elements by being turned ON and OFF, pattern information (22) which defines state combination patterns of the energized state and the non-energized state of the PTC elements with respect to a required power value for the heater unit, and a ratio controlling unit (20) which when the required power for the heater unit is at an intermediate value of the required power values defined in the pattern information, controls a ratio of the energized state to the non-energized state of the PTC elements based on a ratio of ON time to OFF time for which an average power within a certain period matches the required power.