Capacitive Filtering Device for Hybrid Vehicle Power Electronics
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Solution Overview
Problem
The 12V on-board network in electric or hybrid motor vehicles is strongly disturbed by the high voltage network due to electromagnetic compatibility issues, causing coupling with power electronics components, which existing filtering solutions fail to adequately address without increasing the size of the power electronics casing.
Innovation Solution
A capacitive filtering device is integrated upstream of the 12V connectors within the power electronics casing, utilizing a printed circuit with capacitors and a metallic fixing device that connects to the vehicle's ground, allowing for effective filtering of disturbances without enlarging the casing dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a capacitive filtering device is added to filter electromagnetic disturbances, then electromagnetic compatibility is improved, but the space required in the engine compartment increases
Solution Approach 1:
The capacitive filtering device is nested within the existing power electronics housing structure. The filter housing is positioned inside the power electronics housing, utilizing the available internal space without requiring additional external volume. This nesting approach allows the filtering function to be integrated into the existing structure, resolving the contradiction between improving electromagnetic compatibility and maintaining compact dimensions.
2Reliability
If filtering components are added to the power electronics housing, then electromagnetic compatibility is improved, but the device complexity increases
Solution Approach 1:
The capacitive filtering device is merged with the existing power electronics housing and cooling system. The filter housing utilizes the same cooling channels and thermal management infrastructure already present in the power electronics assembly. By combining multiple functions (filtering, cooling, structural support) into a single integrated component, the overall system complexity is minimized while achieving improved electromagnetic compatibility.
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 solution effectively filters disturbances close to the connectors, improving electromagnetic compatibility without increasing the power electronics casing size, ensuring reliable operation of high-voltage chargers between 22kW and 43kW.
Implementation Method 1
a capacitive filtering device comprising a plurality of capacitor elements (32) connected in parallel between said 12V signals and the vehicle ground
Implementation Method 2
it is possible to filter out interference as close as possible to the connector without increasing its size
Data Source
Figure 1~3
Figure 4~5
AI summary
High-voltage charger on board a hybrid or electric motor vehicle comprising a power electronics box (12) comprising a plurality of power electronics modules (14, 16, 18, 20, 22), at least one 12 V connector (26) that is linked by at least one 12 V signal (24) at least to one of the power electronics modules. The high-voltage charger comprises a capacitive filtering device arranged upstream of the 12 V connector (26) in the thickness of the power electronics box (12).