Vehicle PTC Heater Control Housing for EMC and Heat Dissipation
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Solution Overview
Problem
Electrical heating devices for vehicles face challenges with electromagnetic compatibility (EMC) issues and high power losses due to the switching of high currents, which complicates the production and efficiency of these devices.
Innovation Solution
A metallic control housing with a cylindrical design surrounds the printed circuit board, incorporating a separate supporting structure and a compressible compression element to securely fasten the board, ensuring good contact resistance and heat dissipation while minimizing EMC interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high currents are switched to achieve necessary heating performance, then heating output is improved, but electromagnetic interference increases
Solution Approach 1:
The device is divided into two separate housings: a first housing containing the heating elements and a second housing containing the control device with power switches. This spatial segmentation isolates the high-current switching operations from the heating elements, reducing electromagnetic interference while maintaining high heating output capability.
Solution Approach 2:
A metallic connection piece with high electrical conductivity serves as an intermediary between the control device and the heating elements. This connection piece provides a low-impedance path for high currents while being physically separated from the control circuitry, acting as a mediator that enables high power transmission while minimizing electromagnetic interference generation.
2Device complexity
If control device is integrated in structural unit with printed circuit board, then device complexity is reduced, but manufacturing difficulty increases due to high current contacting requirements
Solution Approach 1:
The control device is segregated into a separate second housing with its own printed circuit board and power switches, isolated from the heating elements in the first housing. This segmentation allows each housing to be manufactured and assembled independently, simplifying the overall manufacturing process while ensuring proper contact resistance through dedicated connection interfaces.
Solution Approach 2:
The metallic connection piece acts as an intermediary component that bridges the control device housing and the heating element housing. It provides standardized, pre-engineered contact interfaces that ensure good electrical contact while allowing independent manufacturing of the two housings, thus reducing manufacturing difficulty despite the integrated control functionality.
3Object-affected harmful factors
If control housing is made metallic for EMC shielding, then electromagnetic compatibility is improved, but heat dissipation capability deteriorates
Solution Approach 1:
The device is segmented into two metallic housings that are physically separated by a distance. Both housings provide EMC shielding, and the separation allows heat generated in the heating element housing to dissipate independently without being trapped by an enclosing metallic structure, thus maintaining both EMC performance and heat dissipation capability.
Solution Approach 2:
The metallic connection piece serves as a thermal and electrical intermediary between the two housings. While providing high electrical conductivity for current transmission, its limited size and the air gap between housings allow heat to dissipate from the heating element housing, preventing excessive heat accumulation while maintaining electrical connectivity.
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 enhances the EMC performance, simplifies the manufacturing process, and improves heat dissipation, leading to a more efficient and cost-effective electrical heating device.
Implementation Method 1
the control housing frame surrounds the printed circuit board and is made of a metallic material. In the same way, the control housing cover is preferably formed from a metallic material. In any case, this provides a control housing which externally surrounds the populated printed circuit board and thus shields the components on the coated printed circuit board.
Implementation Method 2
The element that forms the supporting structure carries a compressible compression element, which generates a compressive force acting against the printed circuit board.
Implementation Method 3
The control element generating power loss is located on the side of the printed circuit board facing away from the compression element, preferably between the free end of the support pillar and the cooling element.
Data Source
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AI summary
The present invention relates to a method for manufacturing 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 structural unit with at least one populated circuit board (14) which is received in a control housing (10) and which carries at least one power-loss-generating control element (98). With a view to good thermal contact, the present invention proposes that the power-loss-generating control element (98) be applied under bias against a cooling element (76) formed on the housing (2, 4) during the assembly of the control housing (10) on the housing.