Filter Device Y Capacitor Inductance Reduction via Multi-Core Cable
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing filter device designs, such as those described in PTL 1, face challenges with high inductance due to wiring in the Y capacitor, limiting the arrangement flexibility and requiring a heat radiator near the bus bar, which increases device size and cost.
Innovation Solution
The filter device employs a multi-core cable bundling positive electrode, negative electrode, and ground wirings to connect the Y capacitor to bus bars and a housing ground, reducing inductance and allowing for flexible Y capacitor placement away from the bus bars.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the Y capacitor is arranged near the bus bar to minimize wiring inductance, then the inductance due to wiring is reduced, but the device size increases due to the need for a heat radiator near the bus bar
Solution Approach 1:
The patent segments the wiring system into three separate wires (positive electrode wire, negative electrode wire, and ground wire) that are bundled together. This segmentation allows each wire to be optimized independently while maintaining low inductance through the bundled configuration, enabling the capacitor to be placed away from the bus bar without compromising electrical performance.
Solution Approach 2:
The patent combines the positive electrode wire, negative electrode wire, and ground wire into a single bundled cable assembly. This merging of multiple wires into a compact bundle minimizes the overall inductance while allowing flexible routing away from the bus bar, thus reducing the need for additional heat radiating components and decreasing overall device volume.
2Reliability
If the Y capacitor is arranged near the bus bar to minimize wiring inductance, then the inductance due to wiring is reduced, but the arrangement flexibility is lost
Solution Approach 1:
By segmenting the electrical connections into three separate bundled wires, the patent creates a flexible cable assembly that can be routed to various positions. This segmented approach maintains low inductance through the bundled configuration while enabling the capacitor to be placed at optimal locations away from the bus bar for thermal and spatial reasons.
Solution Approach 2:
The bundled wire configuration provides dynamic routing flexibility, allowing the capacitor to be positioned at multiple locations depending on thermal, spatial, and assembly requirements. The bundled wires can be routed through different paths while maintaining electrical performance, making the system adaptable to various design constraints.
3Temperature
If a heat radiator is added near the bus bar to handle large current, then the heat dissipation is improved, but the device size and cost increase
Solution Approach 1:
The patent extracts the capacitor from the immediate vicinity of the bus bar and places it in a separate location. By taking out the capacitor from the high-heat zone near the bus bar, the need for additional heat radiators is eliminated, as the capacitor can be positioned where natural cooling is sufficient, thereby reducing device volume and cost.
Solution Approach 2:
The bundled wire assembly acts as an intermediary that bridges the electrical connection between the bus bar and the capacitor while allowing spatial separation. This intermediary configuration maintains low inductance electrically while enabling physical separation for thermal management, eliminating the need for additional heat dissipation components.
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 configuration reduces wiring inductance, increases the degree of freedom in Y capacitor placement, and eliminates the need for a heat radiator near the bus bars, maintaining radio frequency performance while minimizing size and cost.
Implementation Method 1
inductance due to wiring from the bus bar up to the Y capacitor
Data Source
AI summary
Since inductance due to wiring to a Y capacitor is large, it is necessary to arrange the Y capacitor near a bus bar, and there is no degree of freedom in arranging the Y capacitor. Directions of currents flowing through a positive electrode side wiring 301 and a negative electrode side wiring 302 in a multi-core cable 300 are a direction 301a from a bus bar positive electrode terminal 114 toward the Y capacitor positive electrode terminal 201, and a direction 302b from a bus bar negative electrode terminal 115 toward the Y capacitor negative electrode terminal 202, respectively. On the other hand, a direction of a current flowing through a ground wiring 303 is a direction 302b from a Y capacitor ground terminal 203 toward a ground terminal 116. A magnetic flux generated by the currents flowing through the positive electrode side wiring 301 and the negative electrode side wiring 302 in the multi-core cable 300 and a magnetic flux generated by the current flowing through the ground wiring 303 in the multi-core cable 300 cancel each other out, and the inductance can be kept small.