Segmented EMI Shield for High Voltage Magnetics
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Solution Overview
Problem
High power magnetics assemblies in galvanically-isolated power converters face challenges with electromagnetic interference (EMI) generation and susceptibility to corona inception, particularly at high voltage potentials, due to the conventional design of magnetic components and interconnects.
Innovation Solution
An EMI suppressing shield system is implemented, comprising multiple shield portions electrically coupled to positive and negative electric potential polarities, with some portions isolated from each other, and a secondary shield connected to ground, to reduce EMI propagation and corona inception by maintaining voltage symmetry and reducing voltage gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional magnetic components and interconnects are used in galvanically-isolated power converters, then the power conversion function is achieved, but electromagnetic interference is generated and corona inception occurs at high voltage potentials
Solution Approach 1:
The shield is divided into multiple electrically isolated portions, each coupled to different voltage potentials (positive, negative, or ground). This segmentation allows each portion to independently manage specific voltage gradients and EMI sources, preventing corona inception while containing electromagnetic interference generated by magnetic components and interconnects.
Solution Approach 2:
The shield portions are electrically coupled to appropriate voltage potentials (positive bus, negative bus, or ground) to maintain equipotential conditions with adjacent high-voltage components. This eliminates voltage gradients between the shield and magnetic components, preventing corona discharge and reducing electromagnetic interference through balanced voltage distribution.
2Object-generated harmful factors
If multiple electrically isolated shield portions are used to suppress EMI, then electromagnetic interference and corona inception are reduced, but the device complexity increases
Solution Approach 1:
The multi-portion shield structure serves multiple functions simultaneously: it shields against electromagnetic interference from magnetic components, maintains voltage symmetry across the galvanically-isolated power converter, prevents corona inception at high voltage potentials, and provides electrical isolation between different voltage domains. This consolidates what would otherwise require separate systems into a single integrated solution.
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 EMI suppressing shield effectively minimizes electromagnetic interference and reduces the probability of corona inception, maintaining balanced voltage conditions and reducing stress on magnetic components, even under ground fault conditions.
Implementation Method 1
An EMI suppressing shield is disclosed that effectively suppresses EMI generated by magnetic components and interconnects
Implementation Method 2
susceptibility to corona inception for components at high voltage potential
Data Source
AI summary
An electromagnetic interference (EMI) suppressing shield is disclosed. The EMI suppressing shield can include a plurality of shield portions electrically coupled to a positive electric potential polarity or a negative electric potential polarity. At least some of the plurality of shield portions can be electrically isolated from one another. At least one of the plurality of shield portions can be electrically coupled to the positive electric potential and at least one of the plurality of shield portions can be electrically coupled to the negative electric potential.