Cast Inductor with Distributed Gap Core for High Frequency Filtering
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Solution Overview
Problem
Existing power filtering systems using traditional inductors overheat due to high frequency harmonics, particularly when metal-oxide-semiconductor field-effect transistors (MOSFETs) or insulated gate bipolar transistors (IGBTs) switch at high frequencies, causing excessive AC resistance and overheating in industrial power cables.
Innovation Solution
A cast inductor apparatus with a distributed gap core and powdered core material is used, which efficiently filters high frequency harmonics by forming a cast winding around an inductor core, allowing for multiple turns wound in parallel, and is designed to operate at frequencies above those usable by traditional steel-based inductors, effectively reducing harmonic attenuation at high currents and voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional steel-based inductors are used for power filtering, then they can handle fundamental frequencies, but they overheat and fail to effectively filter high frequency harmonics due to excessive AC resistance
Solution Approach 1:
The patent changes the core material parameter from traditional steel to powdered core material, and changes the operating frequency parameter to be above the resonant frequency. This allows the inductor to effectively filter high frequency harmonics while avoiding the overheating problem that occurs with traditional steel-based inductors at these frequencies.
Solution Approach 2:
The patent introduces a distributed gap structure in the core, dividing the continuous magnetic path into multiple segments. This segmentation reduces the AC resistance and core losses at high frequencies, preventing overheating while maintaining filtering effectiveness.
2Productivity
If high frequency switching is used in MOSFETs or IGBTs, then power conversion efficiency improves, but AC resistance increases causing severe overheating in power cables
Solution Approach 1:
The patent changes the operating frequency parameter to be in the 50-100 kHz range, which is optimal for high frequency switching applications. This enables efficient power conversion while the distributed gap structure simultaneously prevents excessive AC resistance and cable overheating.
Solution Approach 2:
The patent designs the inductor to dynamically operate above its resonant frequency, adapting to the high frequency switching conditions. This dynamic operation mode allows the inductor to maintain low AC resistance and prevent cable overheating while supporting efficient high frequency power conversion.
3Device complexity
If standard industrial power cables are used for high frequency current, then cable simplicity is maintained, but AC resistance increases causing overheating due to skin effect
Solution Approach 1:
The patent introduces an inductor as an intermediary component in the power system. This inductor with distributed gap structure acts as a mediator that filters high frequency harmonics before they propagate through the power cables, thereby reducing AC resistance losses and preventing cable overheating while maintaining simple cable structures.
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 distributed gap inductor apparatus significantly reduces high frequency harmonic amplitudes, preventing overheating and enhancing energy processing efficiency, while maintaining the passage of fundamental frequencies, thus addressing the limitations of traditional steel-based inductors.
Implementation Method 1
A cast inductor apparatus with a distributed gap core and powdered core material is used, which efficiently filters high frequency harmonics
Implementation Method 2
When frequencies in the 50-100 kHz range are added to the current spectrum, the industrial power cables overheat because of the high frequency travels only on the outside diameter of the conductor causing a severe increase in AC resistance
Data Source
AI summary
The invention comprises a method for manufacturing an inductor, comprising the steps of: casting a cast winding comprising an inner cavity; inserting a first inductor core subsection into the inner cavity; inserting a second inductor core subsection into the inner cavity; and mechanically coupling the first inductor core subsection to the second inductor core subsection to form an inductor core wound by the cast windings. The method of manufacturing optionally includes the steps of: forming at least a portion of the cast winding into an arced helical shape; forming the first inductor core subsection and the second inductor core subsection into elements of a torpid shaped inductor core; deforming the cast winding to physically allow the step of inserting the first inductor core subsection into the inner cavity; and/or deforming at least a portion of the cast winding into an arced helical coil shape after the step of inserting.