PCB Stator Radial Traces Reduce Current Density
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current electric motors and generators face issues with high current density leading to unwanted heat, mechanical failure, and reduced efficiency due to parasitic and eddy currents, which are not adequately addressed by existing strategies in printed circuit board (PCB) designs.
Innovation Solution
The design incorporates a planar composite structure with radially extending conductive traces connected in loops, optimized with a specific corner equation and interconnects to reduce current density concentration and parasitic effects, thereby minimizing electromagnetic field interactions and energy losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high current density is used in PCB windings to increase power output, then power density improves, but parasitic and eddy currents increase causing energy losses and heat generation
Solution Approach 1:
The patent applies curvature by replacing sharp corners with rounded corners in the PCB winding traces. This is achieved by defining specific corner radii (R1, R2, R3, R4) at the intersections of radial and angular traces. The rounded corners smooth the current path, reducing abrupt direction changes that generate eddy currents and parasitic effects, thereby reducing energy losses while maintaining high current density for power density.
Solution Approach 2:
The patent changes geometric parameters of the winding traces, specifically the corner radii (R1, R2, R3, R4) and trace dimensions. By optimizing these parameters, the current distribution is improved, reducing skin effect and proximity effect losses. This allows the system to maintain high current density for power density while minimizing the associated parasitic and eddy current losses through parameter optimization.
2Power
If high current density flow is used to improve power output, then efficiency improves, but temperature gradients increase causing structural damage and delamination
Solution Approach 1:
The rounded corners with specific radii (R1, R2, R3, R4) distribute the current more evenly along the trace paths, avoiding concentration at sharp corners. This reduces localized heating and temperature gradients that would otherwise cause structural damage and delamination in high power output applications.
Solution Approach 2:
The patent applies different corner radii at different locations in the winding pattern. Inner corners have different radii than outer corners, and corners near the center have different radii than those at the periphery. This localized optimization of corner geometry addresses the specific thermal and current distribution requirements at each location, preventing localized overheating and structural damage while maintaining overall high power output.
3Ease of manufacture
If conventional PCB connection strategies are used to make connections between electrical traces, then manufacturing simplicity is maintained, but current density concentration occurs leading to increased electromagnetic fields and reduced efficiency
Solution Approach 1:
The patent maintains manufacturing simplicity by using standard PCB fabrication processes to create rounded corners with defined radii. The corner geometry is integrated into the PCB layout design and manufactured using conventional photolithography and etching processes. This approach reduces electromagnetic field losses and current density concentration through curved geometry while keeping the manufacturing process simple and compatible with existing PCB production capabilities.
Solution Approach 2:
The patent optimizes geometric parameters (corner radii R1-R4, trace widths, spacing) to minimize electromagnetic field losses and current density concentration. These parameter changes are incorporated into the PCB design specifications and manufactured using standard processes, achieving reduced energy losses without compromising manufacturing simplicity.
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 approach significantly reduces energy losses and improves efficiency by distributing current density evenly, achieving up to 90% of maximum current density within 20% of the interconnect length and minimizing parasitic and eddy currents, resulting in enhanced performance across various frequency ranges.
Implementation Method 1
current density flow in regions of the electrical circuit
Implementation Method 2
parasitic or eddy currents, which can lead to mechanical failure
Implementation Method 3
the magnetic field is not strongly confined by magnetically susceptible materials
Implementation Method 4
interaction between fields from adjacent turns in a winding
Implementation Method 5
these high electric current densities act to generate undesirable larger electromagnetic fields
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
The disclosure relates to printed circuit board motors and specifically to printed circuit boards used in motors and generators. Windings formed from copper on printed circuit boards have been used for purposes of forming antennas, inductors, transformers, and stators that can be incorporated in permanent magnet brushless DC (permanent magnet synchronous) machines For energy conversion devices using modern permanent magnet materials and PCB stators, the magnetic field is not strongly confined by magnetically susceptible materials. Thus, the interaction between fields from adjacent turns in a winding, and/or windings on adjacent layers (for a multilayer configuration) may be significant. The structures disclosed hereinafter reduce the effective resistance in the windings, and therefore reduce the associated losses to achieve a reduced current density in portions of the rotating energy conversion devices. The effect of the disclosed structures is a measurable reduction in loss mechanisms as a function increasing frequency, compared to the currently available devices. These effects are significant in frequency ranges important to energy conversion processes as well as typical control strategies, for example, pulse- width modulation.