Inductor Shielding Coil Angle for Near-Field Radiation Reduction
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Solution Overview
Problem
Switched-mode power supplies face challenges in achieving electromagnetic compatibility due to increasing switching frequencies and transition times, leading to excessive electromagnetic field radiation, which existing shielding methods struggle to effectively mitigate.
Innovation Solution
The inductor design incorporates a shielding coil arranged at a specific angle relative to the excitation coil, allowing for efficient attenuation of electric and magnetic fields by positioning the shielding coil to enclose the excitation coil, with adjustable parameters such as number of layers and wire diameter to optimize shielding effectiveness across various frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If switching frequencies and transition times in switched-mode power supplies are increased, then productivity and power efficiency are improved, but electromagnetic field radiation increases causing electromagnetic compatibility problems
Solution Approach 1:
The patent applies the principle of converting harm into benefit by using the electromagnetic fields generated by the excitation coil to induce counteracting fields in the shielding coils. The harmful radiation is transformed into a useful mechanism where the same fields that cause interference are used to generate opposing fields that cancel the radiation, achieving shielding without requiring external shielding structures.
Solution Approach 2:
The shielding coils act as intermediaries between the excitation coil and the external environment. These intermediary coils receive the electromagnetic fields from the excitation coil and transform them into counteracting fields, mediating the interaction between the power supply circuit and the surrounding electromagnetic environment to prevent harmful radiation.
2Object-affected harmful factors
If traditional shielding methods are used to reduce electromagnetic radiation, then electromagnetic compatibility is improved, but device complexity and space requirements increase
Solution Approach 1:
The patent merges the shielding function with the existing inductor structure by integrating shielding coils directly into the inductor assembly. Instead of adding separate external shielding structures, the shielding coils are combined with the magnetic core and excitation coil, creating a multi-functional component that provides both energy storage and electromagnetic shielding.
Solution Approach 2:
The inductor structure is designed to serve multiple functions: the excitation coil provides the primary electromagnetic function while the shielding coils provide electromagnetic compatibility protection. This universal design allows a single component to perform both the power conversion function and the shielding function, eliminating the need for additional dedicated shielding structures.
3Object-affected harmful factors
If shielding coils are added to reduce electromagnetic radiation, then shielding effectiveness is improved, but manufacturing complexity increases
Solution Approach 1:
The patent segments the inductor into distinct functional modules: the excitation coil winding, the magnetic core, and the shielding coils. This segmentation allows each component to be manufactured and prepared separately using standard winding and assembly processes, then combined in a systematic manner, simplifying the overall manufacturing complexity despite the additional shielding functionality.
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 design significantly reduces near-field radiation, offering high shielding effectiveness and flexibility, making it suitable for automotive applications by effectively suppressing electric and magnetic fields in multiple directions.
Implementation Method 1
The excitation coil produces a magnetic field (H-field) which produces according to the Maxwell-Faraday equation an electric field (E-field) in perpendicular direction of the magnetic field and vice versa. Due to the angle δ the at least one shielding coil efficiently suppresses the radiation of E-field and in consequence also the radiation of H-field.
Data Source
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AI summary
An inductor (2) comprises an excitation coil (4) with an excitation coil axis (9) and at least one shielding coil (5) with a respective shielding coil axis (11). The excitation coil axis (9) and the shielding coil axis (11) define an angle δ, wherein applies: 60° ≤ δ ≤ 120°, preferably 75° ≤ δ ≤ 105°, and preferably 85° ≤ δ ≤ 95°. The inductor (2) is shielded and enables in an easy and flexible manner the attenuation of electric and magnetic fields.