PTC Heater Control Housing for EMC Shielding and Heat Dissipation
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Solution Overview
Problem
Electrical heating devices for vehicles face challenges with electromagnetic interference (EMC) and high current switching, which complicates the production and efficiency of heating systems, especially when incorporating a control device with a printed circuit board.
Innovation Solution
A control housing made of metallic materials with a cylindrical design and a compression element to secure the printed circuit board, which includes a support structure and a cooling element for effective heat dissipation, addresses EMC issues and simplifies manufacturing by integrating thermal and electrical connections during assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high currents are switched for heating, then heating performance is improved, but electromagnetic interference increases
Solution Approach 1:
The device is divided into spatially separated functional units: a heating unit with PTC heating elements for high-power heating, and a control unit with printed circuit board for low-power control. This segmentation allows the high-current heating circuit and low-current control circuit to operate independently, reducing electromagnetic interference between them while maintaining high heating performance.
Solution Approach 2:
The control device is extracted from the heating element assembly and placed in a separate control unit. This extraction removes the sensitive control electronics from the high electromagnetic interference environment of the heating elements, allowing high currents to be switched for heating without exposing the control circuitry to harmful electromagnetic effects.
2Object-affected harmful factors
If control device is integrated in structural unit, then EMC problems are reduced, but manufacturing complexity increases
Solution Approach 1:
The device is divided into spatially separated functional units: a heating unit with PTC heating elements for high-power heating, and a control unit with printed circuit board for low-power control. This segmentation allows the high-current heating circuit and low-current control circuit to operate independently, reducing electromagnetic interference between them while maintaining high heating performance.
Solution Approach 2:
A housing structure serves as an intermediary between the heating unit and control unit, providing both mechanical support and electromagnetic shielding. The housing separates the two units while allowing controlled thermal and electrical interactions, simplifying manufacturing by providing a unified structure that addresses both EMC and structural requirements.
3Extent of automation
If control elements are mounted on printed circuit board, then control functionality is improved, but heat dissipation becomes problematic
Solution Approach 1:
The control unit housing is merged with a heat sink structure that is thermally connected to the PTC heating elements. This combination allows the housing to serve dual functions: providing structural support and electromagnetic shielding for the control circuitry, while simultaneously acting as a heat dissipation path for both the control elements and the heating elements.
Solution Approach 2:
A housing structure serves as an intermediary between the heating unit and control unit, providing both mechanical support and electromagnetic shielding. The housing separates the two units while allowing controlled thermal and electrical interactions, simplifying manufacturing by providing a unified structure that addresses both EMC and structural requirements.
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 significantly reduces EMC problems and enhances heat dissipation, improving the heating performance and manufacturing efficiency of electrical heating devices by securely fastening and thermally connecting the control elements to a cooling element within the control housing.
Implementation Method 1
PTC heating elements (92) which can be energized with different polarities
Implementation Method 2
The control housing frame surrounds the printed circuit board (14) and is made of a metallic material. In the same way, the control housing cover (16) is preferably formed from a metallic material. In any case, this provides a control housing (10) which externally surrounds the populated printed circuit board (14) and thus shields the components on the coated printed circuit board (14).
Implementation Method 3
a compression element (112) which generates a compressive force (111) acting against the printed circuit board (14)
Implementation Method 4
the power loss-generating control element (98) is located on the side of the populated circuit board (14) facing away from the compression element (112), preferably between the free end of the support pillar (116) and the cooling element (76)
Data Source
Figure 1
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AI summary
The present invention relates to an electric heating device, particularly for a motor vehicle, comprising a housing (2, 4) enclosing a circulation chamber (32) through which a medium flows, into which heating fins (44) project and which are in thermally conductive contact with at least one PTC heating element (24), and a control unit (11) provided as a single unit with at least one populated circuit board (14) which is housed in a control housing (10). According to the present invention, an improved electric heating device with regard to EMC issues is provided by the control housing (10) comprising a control housing frame (12) that surrounds the populated circuit board (14) and is made of a metallic material, as well as a control housing cover (16).In the method according to the invention, a power loss-generating control element, which is held by the populated circuit board (14), is applied under preload against a cooling element (76) formed on the housing (2, 4) during the assembly of the control housing (10) on the housing (2, 4).