Isolation Transformer Layout for Low Leakage Inductance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Potted isolation transformers face issues with defects in materials leading to transformer failures, poor magnetic coupling, and high inductance leakage due to physical separation of windings, which are undesirable in switching topologies.
Innovation Solution
An isolation transformer design without potting or encapsulation materials, utilizing primary and secondary side wires with different insulation thicknesses and a plurality of magnetic cores to provide voltage isolation, allowing for closer proximity of wires and improved magnetic coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If potted or encapsulation materials are used in isolation transformers, then voltage isolation is achieved, but material defects cause transformer failures and reliability decreases
Solution Approach 1:
The patent removes the potting or encapsulation material from the transformer construction entirely. The isolation transformer is built without these materials, eliminating the source of defects such as cracks, voids, and inclusions that cause transformer failures. The windings are directly assembled on the magnetic core without being embedded in potting compound, thereby extracting the harmful element from the system.
Solution Approach 2:
The patent divides the transformer into discrete components: primary winding, secondary winding, and magnetic core, assembled without a unifying potting material. Each component maintains its structural integrity independently, with insulation provided by wire coating and precise positioning rather than encapsulation. This segmentation eliminates the need for a continuous potting material that could develop defects.
2Reliability
If windings are physically separated in potted transformers, then voltage isolation is provided, but magnetic coupling deteriorates and leakage inductance increases
Solution Approach 1:
The patent employs a nested winding structure where the primary and secondary windings are interleaved and positioned in close proximity around the magnetic core. The windings are nested within each other's magnetic field path, maximizing magnetic coupling while maintaining electrical isolation through proper insulation and spacing. This nested arrangement reduces leakage inductance by ensuring that most magnetic flux links both windings effectively.
Solution Approach 2:
The patent applies different insulation thicknesses to different windings based on their specific voltage requirements. The primary winding may have thicker insulation where high voltage stress occurs, while the secondary winding has insulation appropriate for its voltage level. This localized insulation approach provides adequate voltage isolation without requiring excessive separation between windings, thereby maintaining strong magnetic coupling.
3Reliability
If different insulation thicknesses are used for primary and secondary wires, then voltage isolation requirements are met, but manufacturing complexity increases
Solution Approach 1:
The patent specifies that the primary winding wire has a first insulation thickness and the secondary winding wire has a second insulation thickness, where the thicknesses are selected based on the specific voltage isolation requirements of each winding. This local differentiation of insulation quality allows each winding to have precisely the insulation needed for its voltage stress, avoiding over-insulation and reducing overall complexity compared to using uniform thick insulation throughout.
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 similar voltage isolation to potted transformers without potting materials, offering stronger magnetic coupling and lower leakage inductance, simplifying construction and reducing engineering hours, while meeting application-specific voltage isolation requirements.
Implementation Method 1
a plurality of magnetic cores of magnetic material that can be configured to surround portions of each of the first and second wires along respective circumferences of the first and second wires to provide the isolation transformer
Data Source
AI summary
In some examples, an isolation transformer can include a first wire having a first insulation thickness and a second wire having a second insulation thickness that is different than the first insulation thickness. The isolation transformer can further include a plurality of magnetic cores of magnetic material that can be configured to surround portions of each of the first and second wires along respective circumferences of the first and second wires to provide the isolation transformer.