Power Converter Bus Bar Stack Design for Inductance Reduction
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Solution Overview
Problem
Power converters in electric vehicles and hybrid vehicles face issues due to varying mutual inductance among semiconductor modules, leading to increased inductance and surge voltage, which restricts the size of connections and affects overall performance.
Innovation Solution
A power converter design featuring a stack of positive and negative bus bars with plate-like bodies and extending connecting terminals, where the first and second bus bars are stacked perpendicular to the semiconductor modules, ensuring consistent terminal distances and reducing mutual inductance variation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single metallic plate bus bar is used with multiple connecting terminals, then the structure is simple and manufacturing is easy, but the distance between adjacent connecting terminals decreases when semiconductor modules are closely spaced, restricting connection size
Solution Approach 1:
The bus bar is divided into multiple separate metallic plates (first bus bar, second bus bar, third bus bar) instead of using a single plate. Each bus bar has specific connecting terminals positioned at predetermined locations, allowing independent optimization of each terminal's connection area while maintaining overall structural simplicity.
Solution Approach 2:
The invention utilizes spatial arrangement in multiple dimensions by positioning connecting terminals at different locations across separate bus bars. The first, second, and third connecting terminals are arranged to connect to different semiconductor modules, effectively using the three-dimensional space to maintain adequate connection areas even when modules are closely spaced.
2Area of moving object
If a stack of multiple bus bars is used to increase distance between connecting terminals, then connection area is improved, but inductance variation increases due to different mutual inductance effects on outer vs inner semiconductor modules
Solution Approach 1:
Each bus bar is designed with specific local characteristics - the first bus bar has a first connecting terminal, the second bus bar has a second connecting terminal, and the third bus bar has a third connecting terminal. Each terminal is positioned to connect to specific semiconductor modules, creating localized optimization that collectively achieves uniform inductance across all modules.
Solution Approach 2:
The invention achieves equipotentiality in terms of inductance by carefully designing the connection paths. The first connecting terminal connects to a first semiconductor module, the second connecting terminal connects to a second semiconductor module, and the third connecting terminal connects to a third semiconductor module, ensuring that all semiconductor modules experience equivalent mutual inductance effects despite being at different positions in the stack.
3Quantity of substance
If connecting terminals are placed closer together to accommodate more semiconductor modules, then module density increases, but the size of each connection is restricted
Solution Approach 1:
By segmenting the bus bar into multiple separate metallic plates with dedicated connecting terminals, the invention allows each terminal to maintain adequate connection area while serving different semiconductor modules. This segmentation enables higher module density without compromising individual connection quality.
Solution Approach 2:
The invention resolves the density-connection area tradeoff by utilizing spatial arrangement across multiple dimensions. Instead of placing all terminals close together in a single plane, the first, second, and third connecting terminals are distributed across separate bus bars in the stack, effectively using the vertical dimension to maintain adequate connection areas while accommodating more semiconductor modules.
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 design decreases the variation in mutual inductance among semiconductor modules, thereby reducing the overall inductance of the power converter and improving its performance by equalizing terminal connections.
Implementation Method 1
The inductance of semiconductor modules which are joined to the outer two of the stack of the bus bars is different from that of semiconductor modules which are joined to the inner two of the stack of the bus bars. This arises from a difference in effect of mutual inductance between the bus bars joined to the semiconductor modules.
Data Source
AI summary
A power converter is equipped with a semiconductor module stack, a positive bus bar stack, and a negative bus bar stack. The positive bus bar stack has a first positive bus bar and a second positive bus bar stacked. The negative bus bar stack also has a first negative bus bar and a second negative bus bar stacked in a stacking direction Z of the positive bus bar stack. The first semiconductor modules of the semiconductor module stack are connected to the first positive bus bar and the first negative bus bar, while the second semiconductor modules of the semiconductor module stack are connected to the second positive bus bar and the second negative bus bar. This results in a decreased variation in mutual inductance among the semiconductor modules, which leads to a decrease in overall inductance of the power converter.