Round Laminated Bus Bar for Low-ESL Capacitor Connections
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Solution Overview
Problem
Conventional capacitors with round construction face limitations in high frequency applications due to high equivalent series resistance (ESR) and inductance (ESL), limited operation bandwidth, and internal resonance issues, especially when space is constrained and only the height of the capacitor can be increased.
Innovation Solution
A laminated, overlapped bus bar with a round shape is integrated into the capacitor, comprising multiple layers with an insulation layer to reduce parasitic inductances and resistances, providing a shorter and more equilibrated electric connection, suitable for high frequency applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional flat bands or wires without overlapping are used to connect capacitor windings, then the structure is simple and easy to manufacture, but the equivalent series resistance (ESR) and equivalent series inductance (ESL) are high, limiting operation bandwidth to low frequencies
Solution Approach 1:
The bus bar transitions from a conventional two-dimensional flat band configuration to a three-dimensional laminated structure with multiple overlapping layers. This dimensional evolution enables the bus bar to wrap around cylindrical winding elements, creating extensive overlapping contact areas that significantly reduce ESR and ESL while maintaining manufacturability through standardized layering processes
Solution Approach 2:
The bus bar employs a composite structure combining multiple conductive layers (e.g., copper layers) with insulating layers (e.g., polymer or oxide coatings) between them. This composite design provides both low electrical resistance through the conductive path and electrical isolation between layers, achieving superior electrical performance while preventing short circuits
2Reliability
If the capacitor height is increased to accommodate better internal construction for high frequency applications, then the electrical performance improves, but the overall device volume increases which is not acceptable when space is limited
Solution Approach 1:
The bus bar structure is nested within the existing capacitor housing and winding arrangement. The laminated bus bar layers are positioned between and around the cylindrical winding elements, utilizing the existing internal space without requiring additional vertical clearance. This nested configuration achieves high-frequency performance improvement while maintaining compact overall dimensions
3Reliability
If round-shaped bus bars with laminated structure are used, then parasitic inductances and resistances are reduced for high frequency applications, but the mechanical complexity of integration into round capacitors increases
Solution Approach 1:
The bus bar is segmented into multiple discrete laminated layers that can be independently manufactured and then assembled. Each layer is a simpler component that can be precisely formed and insulated separately, reducing the mechanical complexity of manufacturing the overall bus bar structure while achieving the performance benefits of the laminated configuration
Solution Approach 2:
The bus bar layers are formed with curved surfaces that match the cylindrical geometry of the capacitor windings. This curvature adaptation allows the flat laminated layers to conform to the round shape of the windings, creating optimal contact areas and reducing mechanical complexity by eliminating the need for complex bending or forming operations after assembly
Data Source
AI summary
A bus bar for a capacitor is described, wherein the bus bar is laminated and wherein the bus bar includes a round shape. Furthermore, a capacitor including the bus bar is described.