Toroidal Power Filter with Wound Resistive Element
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Solution Overview
Problem
Conventional power filters face challenges due to bulky wire wound resistors, which increase production time and cost, reduce reliability, and limit pulse power capability, while fragile ceramic substrates in damper resistors compromise reliability and thermal management.
Innovation Solution
A toroidal power filter arrangement featuring a toroidal inductor with a resistive element wound about its outer circumference, providing a resistive pattern with an even number of turns wound in opposite directions, integrated within a housing for enhanced thermal management and compact packaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional wire wound resistors are used in power filters, then pulse power capability is improved, but device size and complexity increase significantly
Solution Approach 1:
The patent combines the inductor and resistor into a single integrated toroidal package. The resistive element is wound directly around the toroidal inductor core, eliminating the need for separate wire harnesses and supports. This merging of components maintains pulse power capability while significantly reducing package complexity and improving reliability.
2Power
If conventional wire wound resistors are used, then pulse power capability is improved, but production time and cost increase
Solution Approach 1:
By integrating the resistor and inductor into a single toroidal package, the number of assembly steps is reduced. The resistive element is pre-positioned on the toroidal core during manufacturing, eliminating subsequent wire harness assembly operations. This streamlining of the manufacturing process directly improves production efficiency while maintaining pulse power performance.
3Reliability
If ceramic base resistors are used, then reliability is improved through solid construction, but thermal management capability deteriorates
Solution Approach 1:
The toroidal core acts as an intermediary thermal management solution. Instead of using ceramic bases that trap heat, the resistive element is wound around the toroidal core which provides a larger surface area for heat dissipation. The core material serves as both the magnetic path for the inductor and the thermal path for the resistor, effectively managing heat without compromising structural reliability.
4Device complexity
If integrated toroidal design is used, then packaging efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The resistive element is wound around the toroidal core in a predetermined pattern during the initial manufacturing stage. This preliminary action ensures that the resistive winding is precisely positioned before final assembly, reducing the need for complex post-assembly adjustments. The even number of turns wound in opposite directions is pre-configured to achieve the desired electrical characteristics while simplifying final assembly operations.
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 enhances reliability and pulse power handling by reducing bulk and increasing packaging efficiency, while the integrated design improves thermal management and reduces production costs.
Implementation Method 1
a power filter arrangement including a toroidal package having a toroidal inductor and a resistive element. The resistive element is disposed about an outer circumference of the toroidal inductor and is joined to the toroidal inductor.
Implementation Method 2
EP1912329 A2 or US2004/233015 A1 disclose toroidal inductors used in filter devices.
Data Source
Figure 1~6
Figure 7A~8
Figure 9~10
AI summary
A power filter arrangement includes a toroidal package having a toroid (82) and a resistive element (84). The resistive element is disposed about an outer circumference of the toroid and is joined to the toroid. The resistive element is wound about the toroid. The resistive element is provided with a first resistive pattern having an even number of total turns.