Integrated DC Link Choke for Common Mode Suppression
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Solution Overview
Problem
Existing power conversion systems face challenges in effectively suppressing common mode and differential mode voltages and currents, leading to degradation and potential damage in motor drives, with existing solutions being costly and space-intensive due to the need for separate devices and complex control systems.
Innovation Solution
A single integrated DC link choke with a core structure having four legs and shunts providing a magnetic flux path between intermediate portions, along with multiple windings, is used to couple the rectifier and inverter, reducing the need for separate differential and common mode devices and simplifying control requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate differential mode inductors and common mode control apparatus are used, then common mode and differential mode suppression is achieved, but system cost and space occupation increase
Solution Approach 1:
The patent combines separate differential mode inductors and common mode control apparatus into a single integrated DC link choke with a unified magnetic core structure. The core includes first and second legs with windings arranged to provide both differential mode inductance and common mode suppression functionality, eliminating the need for separate components and reducing overall system complexity and space requirements
Solution Approach 2:
The integrated DC link choke performs multiple functions simultaneously: it provides differential mode current smoothing through windings on the first and second legs, suppresses common mode voltages through the shared magnetic path, and couples the rectifier and inverter stages. This multi-functional design replaces what would traditionally require separate specialized components
2Reliability
If modification of switching waveforms is used to reduce common mode voltages, then common mode suppression is achieved, but control system complexity increases
Solution Approach 1:
The patent replaces complex active switching control techniques with a passive magnetic solution. The integrated choke's magnetic core structure and winding arrangement automatically suppress common mode voltages through electromagnetic principles, eliminating the need for complicated switching waveform modifications and control algorithms
3Object-affected harmful factors
If isolation transformers are used to address common mode and differential mode noise, then noise suppression is achieved, but system cost and space occupation increase
Solution Approach 1:
The patent integrates noise suppression functionality directly into the DC link choke structure, combining what would traditionally require isolation transformers with separate filtering components into a single unified device. The magnetic core and winding configuration provides both noise suppression and DC link functionality
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 approach reduces core material and copper losses, minimizes component count, and provides effective suppression of common mode voltages without requiring active solutions or complex control, offering a cost-effective and compact solution for power conversion systems.
Implementation Method 1
shunts providing a magnetic flux path between intermediate portions
Implementation Method 2
A first winding forms a first coil of the DC choke and having first and second terminals, with the first winding forming at least one turn around the first leg
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A power conversion system (2) and a DC link choke (100) therefore are presented, in which a continuous core structure (150) is provided with first and second legs (151, 152) around which four or more windings are located, with one or more shunts structures (160) providing a magnetic flux path between intermediate portions of the first and second legs (151, 152).