Nested Magnetic Core EMI Filter for High Current Inverters
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional EMI filters with magnetic cores require significant space and are not suitable for high direct currents, limiting their application in compact designs and high current environments.
Innovation Solution
An EMI filter design featuring a choke with a magnetic inner core and outer core, where conductors are arranged between the cores with gaps to allow magnetic flux completion, enabling effective filtering of both common and differential mode electromagnetic interferences without windings, thus being compact and adaptable to high currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional EMI filters with magnetic cores are used, then electromagnetic interferences can be filtered, but the space requirement increases significantly
Solution Approach 1:
The patent implements nesting by placing the inner magnetic core inside the outer magnetic core, with conductors arranged between them. This nested configuration allows both cores to work together in a compact arrangement, filtering both common-mode and differential-mode electromagnetic interferences without requiring excessive space. The inner core handles differential mode filtering while the outer core provides common mode filtering, achieving dual functionality in a space-efficient manner.
2Object-affected harmful factors
If conventional EMI filters with magnetic cores are used, then electromagnetic interferences can be filtered, but the device cannot handle high direct currents
Solution Approach 1:
The patent applies local quality by creating gaps at specific locations between the magnetic cores and conductors. These gaps are strategically positioned to prevent magnetic saturation while maintaining filtering effectiveness. The gaps allow the device to handle high direct currents by providing magnetic flux paths that avoid saturation, while the magnetic cores continue to effectively filter electromagnetic interferences in both common and differential modes.
3Object-affected harmful factors
If magnetic cores are arranged at conductors to form chokes, then EMI filtering is achieved, but the construction becomes complex and space-consuming
Solution Approach 1:
The patent merges the functions of separate common-mode and differential-mode filtering into a single integrated choke structure. By combining the inner and outer magnetic cores with conductors arranged between them, the design achieves both filtering functions simultaneously without requiring separate components. This unified approach simplifies the overall construction while maintaining effective EMI filtering performance.
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 allows for efficient filtering of electromagnetic interferences in both common and differential modes in a space-saving manner, suitable for high direct currents, with a simplified and compact construction that adapts to current intensity.
Implementation Method 1
The magnetic flux in the common mode is thereby directed around the choke according to the right-hand rule with respect to the current direction of common-mode current in the conductors
Implementation Method 2
The choke is thereby suitable to filter the electromagnetic interferences in the common mode (CM) as well as in the differential mode (DM)
Data Source
AI summary
An inverter for an electric motor may include a capacitor board and at least one electrically conductive contacting unit. The capacitor board may include at least one capacitor and at least one transistor board. The capacitor board and the at least one transistor board may be aligned transversely to a longitudinal direction. The capacitor board and the at least one transistor board may be electrically interconnected. The at least one electrically conductive contacting unit may be configured to contact at least one electrically conductive phase terminal of the motor. The at least one contacting unit may be connected to the at least one transistor board in an electrically conductive manner. The at least one contacting unit may be resilient in the longitudinal direction.