Planar PCB Transformer With Ceramic Isolation and Embedded Cooling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing medium voltage AC to DC converters in electric vehicle charging stations face challenges such as high eddy current and AC losses, high voltage isolation requirements, parasitic resistances and capacitances, and cooling inefficiencies in transformers, which affect efficiency and reliability.
Innovation Solution
A planar transformer design using magnetic cores, printed circuit boards, ceramic insulation, and embedded cooling tubes, along with dual active bridge modules, to minimize losses and enhance isolation and cooling, while utilizing MOSFET transistors for efficient power transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If LITZ wire is used to reduce eddy current losses, then eddy current losses are reduced, but the insulation occupies a large percentage of the winding space and cost increases
Solution Approach 1:
The patent replaces traditional LITZ wire construction with planar PCB-based windings. The PCB traces serve as conductors with inherent insulation from the substrate, eliminating the need for individual strand insulation while maintaining low eddy current losses through the planar geometry and controlled trace configurations.
Solution Approach 2:
The patent uses composite construction combining PCB substrate (insulating material) with copper traces (conductive material) to create an integrated winding structure. This composite approach provides both electrical functionality and insulation in a single component, reducing overall insulation space requirements compared to traditional LITZ wire assemblies.
2Reliability
If high voltage isolation is implemented using large creepage and clearance distances, then voltage isolation is improved, but the transformer size increases
Solution Approach 1:
The patent applies different insulation strategies to different regions: ceramic insulators are placed specifically at high-stress isolation points between primary and secondary windings, while PCB substrates provide distributed insulation throughout the winding structures. This localized quality approach achieves high voltage isolation without uniformly increasing all dimensions.
Solution Approach 2:
The patent employs asymmetric insulation placement where thick ceramic insulators are positioned only where maximum voltage stress occurs (between primary and secondary), rather than uniformly throughout. The PCB windings themselves provide asymmetric insulation profiles optimized for their specific electrical stress environments.
3Reliability
If continuous solid insulation is used between layers for high voltage isolation, then voltage isolation is improved, but parasitic capacitance increases
Solution Approach 1:
The patent segments the insulation system into discrete components: thin PCB substrate insulation between adjacent turns, and thicker ceramic insulator segments at isolation boundaries. This segmentation reduces continuous insulation paths and associated parasitic capacitance while maintaining necessary voltage isolation through the segmented structure.
4Temperature
If liquid cooling or heat pipes are employed, then cooling efficiency is improved, but eddy current losses increase due to metal placement
Solution Approach 1:
The patent introduces non-conductive PCB substrates as intermediary structures between the cooling system and conductive windings. The PCB acts as a thermal mediator that conducts heat away from the windings while its insulating properties prevent eddy current formation, solving both cooling and loss reduction requirements.
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 reduced eddy current losses, improved isolation, and efficient cooling, resulting in enhanced efficiency and reliability for high-power medium-voltage applications.
Implementation Method 1
a magnetic core, planar windings composed of one or more printed circuit boards (PCBs)... The magnetic core extends entirely around the windings
Implementation Method 2
A ceramic electrical insulator electrically separates the primary and secondary windings
Implementation Method 3
an embedded cooling tube... The embedded cooling tube could also be a heat pipe
Implementation Method 4
The embedded cooling tube could also be a heat pipe... package the transistors as bare die in a transistor die assembly that reduces the thermal resistance between the bare die and the coolant
Data Source
AI summary
A protective enclosure for electrical components includes potting material encasing the electrical components. A case covers the potting material. At least one clastic component extends over the case for applying a compressive load to the potting material.