WBG Power Stage PCB Packaging for Thermal Isolation and EMI Control
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Solution Overview
Problem
Designing wide bandgap (WBG) power electronic systems that are both power-dense and temperature-resistant poses challenges due to the temperature sensitivity of film capacitors, making it difficult to reduce the size of these systems while ensuring reliability and efficiency.
Innovation Solution
The design incorporates a vertically stacked multi-board control system, tightly grouped circuitry, perpendicular routing of current carrying traces, ferrite cores for noise reduction, and a dielectric thermal interface material (TIM) with high thermal conductivity to decouple the capacitor bank from power switches, along with mini-manifolds and channels for efficient cooling, resulting in a compact, high-efficiency SiC inverter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If film capacitors are used in WBG power electronic systems, then the system can achieve higher power density and smaller size, but the system becomes temperature-sensitive and less reliable at high temperatures
Solution Approach 1:
The patent extracts the capacitor bank from the high-temperature environment by physically separating it from the power switches. The capacitor bank is positioned in a separate cooling zone with dedicated cooling channels, isolating it from the thermal field generated by the power switches. This extraction allows the use of temperature-sensitive film capacitors while maintaining high-temperature operation of the power stage.
Solution Approach 2:
The patent introduces a dielectric thermal interface material as an intermediary between the capacitor bank and the heat sink. This material provides both thermal conduction for heat dissipation and electrical insulation for safety. The intermediary enables the capacitor bank to operate at lower temperatures while the power switches can operate at higher temperatures, resolving the temperature sensitivity issue.
2Volume of moving object
If power switches and capacitor bank are placed close together, then the system achieves higher power density, but electromagnetic interference increases
Solution Approach 1:
The patent introduces a dielectric barrier as an intermediary between the power switches and capacitor bank. This barrier provides electrical insulation while allowing thermal conduction, enabling close placement of components for high power density while preventing electromagnetic interference. The dielectric material acts as a mediator that blocks electrical fields while permitting heat transfer.
Solution Approach 2:
The patent segments the internal structure into distinct functional zones: a power switch zone with dedicated cooling channels, a capacitor bank zone with separate cooling pathways, and dielectric barrier zones separating them. This segmentation allows close proximity for compactness while maintaining electromagnetic isolation through the dielectric barriers between segments.
3Temperature
If cooling channels are increased to manage heat from power switches, then temperature control improves, but the system size increases
Solution Approach 1:
The patent implements local quality by providing dedicated cooling channels specifically for the power switches in high-heat-generation zones, while the capacitor bank has separate, optimized cooling pathways. This localized cooling approach efficiently manages heat where it is generated without requiring a uniform increase in overall cooling system size. Each component receives targeted thermal management.
Solution Approach 2:
The patent utilizes three-dimensional vertical stacking to arrange power switches and capacitor banks in different vertical layers with interleaved cooling channels. This dimensional arrangement allows efficient heat removal from power switches through bottom cooling while capacitors receive top cooling, achieving superior temperature control without increasing the horizontal footprint of the system.
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 achieves greater than 98% efficiency, reduces electromagnetic interference, and allows the SiC inverter to operate at higher temperatures with increased power density and reduced size, while effectively managing heat and noise, enabling rapid response to faults and improved reliability.
Implementation Method 1
a dielectric barrier in the form of a thermally conductive electrically insulating material between the capacitor bank and the heat sink
Implementation Method 2
ferrite cores for noise reduction
Implementation Method 3
mini-manifolds and channels for efficient cooling
Data Source
AI summary
Design and packaging of wide bandgap (WBG) power electronic power stages are disclosed herein. An example apparatus includes a first printed circuit board (PCB) including: a first voltage phase circuit cluster; a second voltage phase circuit cluster; and a cluster of traces, the cluster of traces routed substantially perpendicular to the second voltage phase circuit cluster; a second PCB positioned below the first PCB; and a connector to connect the first PCB to the second PCB, the connector electrically coupled to the first voltage phase circuit cluster by the cluster of traces.