Cable Harness Damping Device for Electric Drive EMC
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Solution Overview
Problem
Conventional EMC filters fail to effectively dampen interference signals caused by cable harness resonances in electric vehicles, leading to electromagnetic compatibility issues despite power electronics not generating emissions, as they do not account for external cable harness resonances.
Innovation Solution
A damping device with a specific topology that includes dipoles connected to the cable wires and ground, and optionally to other wires, using an impedance matrix for capacitive and inductive isolation, and incorporating inductances like SMD ferrites or CM cores to manage modal wave impedances and resonance modes, thereby reducing interference emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional EMC filters are used to damp interference signals from power electronics, then the filter can damp source emissions, but cable harness resonances remain undamped and continue to radiate interference
Solution Approach 1:
The patent extracts the cable harness from the treatment scope of conventional EMC filters and applies dedicated damping measures (dipoles Zkk and Zkm) specifically to the cable harness structure. This separates the damping function into two parts: conventional filters for power electronics and dipoles for cable harness resonances, thereby resolving the contradiction by addressing the previously neglected cable harness interference source.
Solution Approach 2:
The patent introduces dipole structures (Zkk and Zkm) as intermediary elements connected between cable harness wires and ground or between wires. These dipoles act as mediators that specifically target and damp cable harness resonances without interfering with the function of conventional EMC filters, enabling simultaneous damping of both power electronics emissions and cable harness resonances.
2Device complexity
If conventional EMC filters are designed only for power electronics, then the filter structure remains simple, but it fails to account for cable harness resonances which amplify emissions at certain frequencies
Solution Approach 1:
The patent segments the EMC filtering function into two distinct parts: conventional EMC filters for power electronics and additional dipole structures (Zkk, Zkm) for cable harness resonances. This segmentation allows each component to be optimized for its specific function while maintaining overall system effectiveness, addressing the contradiction by expanding the filter system in a structured, modular way.
Solution Approach 2:
The patent introduces frequency-dependent dipole structures that dynamically respond to cable harness resonances at specific frequencies. The dipoles are designed with specific impedance characteristics that vary with frequency, enabling them to selectively damp resonance modes without affecting the entire frequency spectrum, thus managing complexity while targeting specific harmful frequencies.
3Reliability
If the damping device uses a full impedance matrix with all possible dipoles, then all resonance modes can be damped, but the device complexity increases significantly
Solution Approach 1:
The patent applies local quality by selectively placing dipoles only where cable harness resonances occur, rather than uniformly across all possible connections. The impedance values of the dipoles are locally optimized based on the specific resonance characteristics of each cable segment, enabling effective damping with fewer elements and reducing overall device complexity while maintaining comprehensive resonance suppression.
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 effectively dampens both common-mode and differential-mode resonances, reducing interference by up to 50 decibels, ensuring improved electromagnetic compatibility in electric vehicles by accounting for the cable harness properties and resonance modes.
Implementation Method 1
A damping device according to the invention is designed to damp interference signals in a cable having a plurality of wires
Implementation Method 2
The resistance and the reactance of the dipoles Zkm, Zkk are determined as follows: [admittance matrix equations]
Implementation Method 3
The resonances in the connecting structures, in particular in the cable harnesses, amplify the emissions at certain frequencies
Implementation Method 4
The damping device has the topology of an impedance matrix with a capacitive and an inductive isolation in the lower frequency range
Implementation Method 5
incorporating inductances like SMD ferrites or CM cores to manage modal wave impedances
Data Source
AI summary
A damping device is designed to dampen noise signals in a cable having a plurality of wires. The damping device includes a plurality of first terminals, to which is applied the voltage vector U1 and where the current vector I1 flows, a wire of the cable being connected to each first terminal; a plurality of second terminals, to which is applied the voltage vector U2 and where the current vector h flows, a wire of the cable being connected to each second terminal; and a first plurality of dipoles, whose first terminal is connected to the wire k and whose second terminal is connected to ground.