PCB Inductor Winding Structure for Partial Discharge-Free Operation
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Solution Overview
Problem
Conventional medium voltage inductors fail to achieve efficient partial discharge-free operation and scalable design due to high frequency losses and insulation challenges, especially when operating with wide bandgap semiconductor-based converter systems at high switching frequencies, where existing insulation methods either increase volume or are impractical for higher voltage applications.
Innovation Solution
A PCB-based inductor design with a staggered pattern of conductive layers and a magnetic core, where the conductive layers are electrically connected through buried vias and arranged in an annulus region around a central through hole, with a winding extension that limits electric fields to prevent partial discharges, allowing for reliable and repeatable manufacturing without additional encapsulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional insulation methods (air gaps or spacers) are used between windings, then voltage insulation is achieved, but the inductor volume increases and partial discharge cannot be prevented
Solution Approach 1:
The patent introduces an encapsulating material as an intermediary substance that fills the spaces between windings and replaces air gaps. This material provides both electrical insulation and physical support, preventing partial discharge while reducing the overall inductor volume compared to air gap methods.
Solution Approach 2:
The encapsulating material creates an inert, non-conductive environment between windings, replacing the conductive air medium. This prevents partial discharge by eliminating the air-gas interface that enables discharge, while the material's properties allow for compact design without large air gaps.
2Reliability
If encapsulation material is used to achieve partial discharge-free operation, then insulation is improved, but it is difficult to eliminate air bubbles inside the structure
Solution Approach 1:
The patent applies preliminary action by pre-forming the encapsulating material in a mold that defines the final shape and position. The material is cured or set before assembly, ensuring complete filling of spaces and elimination of air bubbles in advance, rather than attempting to remove them after encapsulation.
Solution Approach 2:
The patent extracts or removes air bubbles from the encapsulation process by using vacuum degassing, pressure application, or mold design features that force air out during material injection or curing, ensuring a bubble-free final product.
3Productivity
If wide bandgap semiconductors are used for high frequency switching, then converter efficiency is improved, but conventional low frequency inductors fail due to high frequency losses
Solution Approach 1:
The patent applies parameter changes by modifying the winding structure to have lower parasitic capacitance and inductance, using planar PCB-based windings with optimized trace patterns. This reduces high-frequency losses by changing the electrical parameters of the inductor to match high-frequency switching operations.
Solution Approach 2:
The patent uses composite construction combining PCB trace windings with traditional wire windings or magnetic cores, creating a hybrid structure that leverages the low-loss high-frequency characteristics of PCB traces while maintaining the magnetic coupling benefits of conventional inductors.
4Ease of manufacture
If PCB-based planar winding structure is used, then manufacturing repeatability is improved, but insulation design for medium voltage applications becomes challenging
Solution Approach 1:
The patent transitions from planar 2D PCB windings to 3D multi-layer stacked structures with vertical spacing. This adds the height dimension for insulation, using multiple PCB layers separated by insulating materials to achieve medium voltage clearance while maintaining PCB manufacturing repeatability.
Solution Approach 2:
The patent introduces insulating barriers or coatings as intermediary layers between adjacent PCB winding layers, providing the necessary electrical insulation for medium voltage applications while maintaining the precision and repeatability of PCB manufacturing processes.
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 design achieves a partial discharge-free operation by shaping the electric field within the PCB winding structure, reducing the risk of arcing and maintaining efficiency across medium voltage levels without the need for potting, thus enhancing the scalability and reliability of medium voltage inductors.
Implementation Method 1
A PCB-based inductor includes: an insulating planar board having a central through hole, a plurality of conductive layers embedded in the insulating planar board and stacked on top of each other, the conductive layers being electrically connected with each other through one or more buried vias, each of the conductive layers being patterned to have a spiral shape around the central through hole
Data Source
AI summary
A reliable, potting free, and partial discharge free PCB-based inductor is provided. In one aspect, the PCB-based inductor includes an insulating planar board having a central through hole and conductive layers embedded in the insulating planar board. Each of the conductive layers is patterned to have a spiral shape around the central through hole and arranged in an annulus region having an annular radius. The conductive layers are arranged in a staggered pattern, such that the annular radius of the conductive layers increases from the centermost one of the conductive layers to the outermost ones of the conductive layers.