Stacked Power Terminal Structure for Reduced DC Loop Inductance
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Solution Overview
Problem
Stray inductance in the DC+/DC− power terminal loop of power electronics modules, such as inverters in electric vehicles, negatively affects switching speed and power efficiency.
Innovation Solution
The arrangement of power terminals with mutually conforming shapes, such as beams or flat plates, stacked with a narrow gap (1-2 mm) and secured by insulating materials, reduces stray inductance by minimizing the loop area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If power terminals are arranged in a traditional layout, then the module structure is simple, but the stray inductance in the DC+/DC− power terminal loop is high, negatively affecting switching speed and power efficiency
Solution Approach 1:
The power terminals are arranged in a stacked configuration where the DC+ terminal and DC− terminal are positioned one above the other in the vertical dimension, rather than side-by-side in the horizontal plane. This dimensional change minimizes the loop area formed by the current path, thereby reducing stray inductance while maintaining structural simplicity
Solution Approach 2:
The DC− terminal is positioned within the horizontal footprint of the DC+ terminal, creating a nested arrangement where one terminal is effectively 'inside' the projection of the other. This nesting minimizes the external loop area and concentrates the current path, reducing stray inductance
2Loss of energy
If power terminals are placed close together to reduce loop area, then stray inductance is reduced, but the risk of electrical breakdown or arcing between terminals increases
Solution Approach 1:
An insulating material is introduced as an intermediary substance positioned between the DC+ terminal and DC− terminal in the stacked arrangement. This mediator provides electrical insulation and prevents arcing while allowing the terminals to remain in close proximity for minimal loop area and low stray inductance
Solution Approach 2:
The insulating material used between the terminals is a simple, cost-effective solution that can be easily integrated into the terminal structure. While the insulating material may have limited durability under extreme conditions, it provides sufficient protection for the operational lifetime of the module and can be replaced if necessary
Data Source
AI summary
A module includes a power circuit enclosed in a casing. A first power terminal and a second power terminal of the power circuit each extend to an exterior of the casing. The first power terminal and the second power terminal separated by a gap are disposed in a stack on the exterior of the casing.