Bus Bar Design for Electric Power Converter Inductance
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Solution Overview
Problem
Conventional electric power converters face issues with shortened extended portions in the stacking direction when the pitch is narrowed, leading to increased parasitic inductance and potential voltage surges during semiconductor element switching.
Innovation Solution
The electric power converter employs a bus bar formed from multiple plate members with extended portions and terminal connecting portions, where the terminal connecting portions are perpendicular to the stacking direction, allowing for a wider pitch between connections and preventing elongation of the extended portions, thereby suppressing parasitic inductance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the pitch of the stacked body is narrowed, then the compactness of the electric power converter is improved, but the length of the extended portion in the stacking direction is shortened
Solution Approach 1:
The bus bar structure transitions from a planar configuration to a three-dimensional configuration by adding vertical extension in the stacking direction. The extended portion extends vertically from the main body, utilizing the third dimension to maintain sufficient length while accommodating narrower pitch between stacked semiconductor modules.
2Productivity
If the length of the extended portion is shortened, then the pitch can be narrowed, but the parasitic inductance is increased
Solution Approach 1:
The bus bar extends in the vertical stacking direction rather than only in the lateral direction. This dimensional change allows the extended portion to achieve sufficient length for low inductance while the horizontal pitch between modules can be reduced for compactness.
3Object-affected harmful factors
If the extended portion is elongated to compensate for shortened length, then the parasitic inductance can be reduced, but the voltage surge risk is increased
Solution Approach 1:
By extending the bus bar vertically in the stacking direction rather than laterally, the design achieves sufficient effective length for low parasitic inductance while maintaining controlled impedance and reducing voltage surge risks associated with excessive lateral elongation.
Data Source
AI summary
An electric power converter has a stacked body formed by stacking a plurality of semiconductor modules and coolers, a capacitor, and positive and negative bus bars. Each of the bus bars is formed by two sheets of plate members, respectively. Each of the plate members has a body portion, a plurality of extended portions, and a plurality of terminal connecting portions. The terminal connecting portions are connected to power terminals of the semiconductor modules. The main body portion of each plate member are joined to each other so that the terminal connecting portion of the one of the plate members and the terminal connecting portion 44 of the other one of the plate member are disposed alternately in a stacking direction of the stacked body.