Self-Centering Inductor for Class-D Audio Amplifier Eddy Current Loss
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Solution Overview
Problem
Conventional inductors used in Class-D audio amplifiers suffer from negative performance parameters such as heating and power loss due to eddy currents caused by inconsistent wire core assembly, leading to suboptimal performance in demodulation filters.
Innovation Solution
The design features ferrite core pieces with self-locating and self-centering wire core assemblies, made from flat magnet wire wound in a spiral manner, which compresses to fit within the core channels, ensuring a uniform and constant distance between the wire core and the core walls, minimizing eddy currents and enhancing magnetic characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional wire core assembly is used in inductor, then manufacturing is simpler, but eddy current losses and heating increase due to inconsistent positioning
Solution Approach 1:
The wire core assembly is segmented into multiple wire cores arranged in a specific pattern, with each wire core positioned in a dedicated channel. This segmentation allows for consistent positioning of each wire core relative to the ferrite core, reducing eddy current losses while maintaining manufacturing simplicity.
Solution Approach 2:
Wire core channels act as intermediaries between the wire core assembly and the ferrite core. These channels provide precise positioning and support for the wire cores, ensuring uniform spacing and consistent electrical characteristics, thereby reducing eddy current losses without complicating the overall assembly process.
2Manufacturing precision
If wire core assembly with variable spacing is used, then manufacturing is easier, but performance deteriorates due to inconsistent magnetic characteristics
Solution Approach 1:
The wire core channels are pre-formed with precise dimensions and positions during ferrite core manufacturing. This preliminary action ensures that when wire cores are inserted, they automatically achieve consistent spacing and positioning, improving manufacturing precision while keeping the assembly process simple.
Solution Approach 2:
The wire core channels are designed to self-align and self-position the wire cores during assembly. The channels' geometry naturally guides the wire cores into correct positions, eliminating the need for complex alignment procedures or additional fastening mechanisms, thus maintaining ease of manufacture.
3Loss of energy
If larger wire core assembly is used to reduce resistance, then power loss decreases, but device size increases
Solution Approach 1:
The wire core assembly uses an asymmetric arrangement of multiple wire cores with different cross-sectional areas. Some wire cores have larger cross-sections to carry higher currents, while others are smaller. This asymmetric design reduces overall power loss by optimizing current distribution without proportionally increasing the inductor's external dimensions.
Solution Approach 2:
Instead of increasing wire core size in one dimension, the invention distributes multiple wire cores across different spatial positions within the ferrite core. This dimensional distribution allows for reduced total resistance and power loss while maintaining a compact inductor footprint, as the current path is extended through multiple parallel wire cores rather than enlarging a single core.
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 core losses, eddy current losses, and costs associated with construction, while allowing for denser packaging and improved performance in Class-D audio amplifiers by minimizing electromagnetic interference and crosstalk.
Implementation Method 1
the wire core assembly, when uncompressed, has an outer radius that is larger than the radius of the channel, such that when the leads are allowed to return to their uncompressed state, the wire core assembly expands to fit substantially immovably against the outer wall
Implementation Method 2
conventional inductor 100 suffers from negative performance parameters such as heating and power loss due to eddy currents caused by inconsistent wire core assembly
Implementation Method 3
ferrite core pieces, each of which are made of substantially similar materials, exhibit desired electromagnetic properties
Implementation Method 4
first ferrite core piece and a second ferrite core piece, each of which are made of substantially similar materials, exhibit desired electromagnetic properties
Data Source
AI summary
An inductor is provided, comprising: a first ferrite core piece and a second ferrite core piece, each of which are made of substantially similar materials, exhibit desired electromagnetic properties, and which are fashioned in a substantially similar manner and shape, and wherein each of the first and second ferrite core pieces comprises a substantially planar mating surface, a center post, and a wire core assembly channel, and wherein a first substantially planar mating surface of the first ferrite core piece is adapted to planarly mate with a second substantially planar mating surface of the second ferrite core piece; and a wire core assembly adapted to be substantially self-locating and self-centering about a first or second center post when located in a respective first or second wire core assembly channel.