Insulative Device for Power Semiconductor Modules
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Solution Overview
Problem
Conventional signal transmission insulating devices with thin film transformer structures face challenges in increasing insulation withstand voltage without compromising signal transmission characteristics, as electric field concentration at coil corners leads to insulation breakdown, necessitating excessive film thickness and reduced signal transmission speed.
Innovation Solution
The implementation of a signal transmission insulating device with a layered insulating film structure, where the first coil is surrounded by second and third insulating films with lower resistivity and higher permittivity than the primary insulating film, effectively dispersing electric field concentration and mechanical stress, thereby increasing insulation withstand voltage without increasing film thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the insulating film is increased to ensure predetermined withstand voltage, then insulation withstand voltage is improved, but the distance between upper coil and lower coil becomes long causing signal transmission characteristics to decrease
Solution Approach 1:
The patent applies local quality by providing second and third insulating films with different material properties (lower resistivity, higher permittivity) specifically at the corner regions where electric field concentration occurs, while the first insulating film maintains the basic insulation function. This localized enhancement of insulating properties at critical stress points allows for adequate withstand voltage without uniformly increasing the distance between coils, thereby preserving signal transmission characteristics.
Solution Approach 2:
The patent employs composite materials by combining multiple insulating films with different dielectric properties. The first insulating film (higher resistivity) provides baseline insulation, while the second and third insulating films (lower resistivity, higher permittivity) are strategically positioned to address electric field concentration. This composite structure optimizes both insulation withstand voltage and signal transmission performance.
2Reliability
If the thickness of the insulating film is increased to account for electric field concentration at coil corners, then insulation reliability is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent segments the insulating film structure into distinct functional layers: a first insulating film for baseline insulation and second/third insulating films specifically positioned at corner regions to address electric field concentration. This segmentation allows each layer to perform its specialized function efficiently, improving reliability without requiring a uniform increase in overall film thickness that would complicate manufacturing.
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 configuration alleviates electric field concentration at coil corners, enhancing insulation withstand voltage and maintaining signal transmission characteristics, such as speed and intensity, by using SiN films for the second and third insulating layers in conjunction with SiO2 for the primary film.
Implementation Method 1
electric field concentration occurs at each corner of each of the upper coil and the lower coil
Implementation Method 2
a second insulating film including a first film provided between the first insulating film and a surface in contact with a second principal surface of the first coil
Data Source
AI summary
A signal transmission insulating device includes: a first coil; a second coil opposing the first coil to form a transformer together with the first coil; a first insulating film provided between the opposing first coil and second coil and made of a first dielectric material; a second insulating film surrounding the first coil and made of a second dielectric material having a lower resistivity or a higher permittivity than the first dielectric material; and a third insulating film surrounding the second coil and made of a third dielectric material having a lower resistivity or a higher permittivity than the first dielectric material.