Surge Blocking Inductor With Counter-Wound Coils
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Solution Overview
Problem
Existing power converters face challenges in surviving high voltage surges and electromagnetic interference due to the saturation of inductors used in surge protection networks, which limits their effectiveness and increases production costs and reliability issues.
Innovation Solution
A new inductor structure comprising two counter-wound coils on a common core, optimized for maximum saturated inductance and energy dissipation, with air gaps and a shield layer to enhance energy dissipation and reduce resonance, providing both surge protection and EMI filtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional inductors are used in surge protection networks, then voltage clamping is achieved, but the inductors saturate quickly under surge current, reducing their effectiveness
Solution Approach 1:
The inductor is divided into multiple segments with individual magnetic cores that can be independently saturated. This segmentation allows the total surge current to be distributed across multiple cores, preventing any single core from saturating quickly and maintaining inductance for longer duration surge protection.
Solution Approach 2:
The patent uses composite magnetic core structures combining different magnetic materials with different saturation characteristics. This allows the inductor to utilize the full saturation capacity of each core material, increasing the overall current handling capability before saturation occurs.
2Reliability
If multiple protection components (clamps, inductors, capacitors) are added to meet surge standards, then voltage protection is improved, but production costs increase and reliability decreases due to more failure points
Solution Approach 1:
The surge protection inductor is designed to perform multiple functions simultaneously: voltage clamping during surges, EMI filtering during normal operation, and energy dissipation. This multi-functionality eliminates the need for separate protection components, reducing component count while maintaining or improving protection effectiveness.
Solution Approach 2:
The patent merges the surge protection function with the existing EMI filter inductor into a single component. By combining these functions, the design reduces the total number of components needed in the power converter while achieving both surge protection and EMI filtering requirements.
3Strength
If air gaps are added to the magnetic core to prevent saturation, then current handling is improved, but inductance value decreases and device size increases
Solution Approach 1:
By segmenting the magnetic path into multiple smaller cores with individual air gaps, the patent achieves better utilization of magnetic material. Each segment operates at optimal flux density, allowing smaller overall size while maintaining high current handling capability through the combined effect of multiple segments.
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 inductor structure effectively blocks high surge currents, reduces voltage rating requirements, and enhances EMI filtering, leading to cost and efficiency savings while improving the reliability of power converters.
Implementation Method 1
The structure comprises two counter-wound inductors wound on a common core such that the coils are coupled magnetically when the common core is saturated
Implementation Method 2
optimized for maximum saturated inductance and energy dissipation, with air gaps and a shield layer to enhance energy dissipation
Implementation Method 3
with air gaps and a shield layer to enhance energy dissipation and reduce resonance
Data Source
AI summary
A surge blocking inductor. In one embodiment, the surge blocking inductor includes a core; a first winding wound about the core in a first direction; and a second winding wound about the core in a second direction, wherein the first winding and the second winding are magnetically independent when the core is in a non-saturated state, and wherein the first winding and the second winding are coupled magnetically when the core is in a saturated state.