PTC Heater Heat Rod Layout for PWM Noise Reduction
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Solution Overview
Problem
High noise levels are generated by PTC heaters during PWM control due to collisions of PTC elements at the same positions in adjacent heat rods, especially at high voltage operations, leading to reduced efficiency and thermal saturation as the heater capacity increases or size decreases.
Innovation Solution
The PTC elements in adjacent heat rods are mismatched in their center lines in the height direction to minimize overlapping regions, allowing them to be spaced apart and form columns and rows in a single layer, reducing noise and maintaining heat generation capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If PTC elements are disposed at the same positions in adjacent heat rods to maximize heat generation capacity, then the heating efficiency is improved, but noise is increased due to collisions between PTC elements during PWM control
Solution Approach 1:
The patent applies asymmetry by intentionally misaligning the positions of PTC elements in adjacent heat rods. Specifically, PTC elements in alternate heat rods are offset from each other in the height direction, creating an asymmetric configuration that prevents direct overlap and collision during vibration, thereby reducing noise while maintaining effective heating capacity through the combined arrangement of multiple heat rods.
2Power
If the capacity of the PTC heater is increased to meet user demand, then the heating performance is improved, but thermal saturation occurs more easily and noise increases
Solution Approach 1:
The patent segments the heating system into multiple independent heat rods, each containing multiple PTC elements arranged in a single layer. This segmentation allows the total heating capacity to be distributed across multiple units, preventing any single PTC element from generating excessive heat that would lead to thermal saturation, while the cumulative effect of all heat rods provides the required high heating capacity.
3Volume of moving object
If the size of the PTC heater is reduced to make it compact, then the space efficiency is improved, but the distance between heat rods becomes narrower causing increased noise and thermal saturation
Solution Approach 1:
The patent transitions from a traditional multi-layer stacking arrangement to a single-layer configuration where PTC elements are arranged in the height direction within each heat rod. This dimensional change allows heat rods to be positioned closer together in the horizontal plane without causing PTC element overlap, enabling a more compact overall heater design while maintaining adequate spacing to prevent noise and thermal saturation.
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 configuration effectively decreases noise and prevents thermal saturation, improving the operational efficiency of the PTC heater by minimizing overlapping regions and adjusting the number and capacity of PTC elements in each heat rod.
Implementation Method 1
a PTC heater, using a positive temperature coefficient (PTC) element, allows the heating to be performed using electric energy of a battery
Data Source
AI summary
A positive temperature coefficient heater includes PTC elements embedded in adjacent heat rods, the PTC elements of the adjacent heat rods include center lines mismatched with each other and configured to minimize regions in which the PTC elements are overlapped with each other in the heat rods in which a plurality of PTC elements spaced apart from each other so as to form columns and rows and arranged in a single layer are embedded.