Parallel Power Devices in Inverter Modules
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Solution Overview
Problem
Power modules with long bus bars exhibit high parasitic inductance and resistance, leading to inefficiencies such as ringing and power losses due to the parallel connection of power devices.
Innovation Solution
A power drive apparatus and module design featuring power devices arranged in a back-to-back configuration within stacked rows, utilizing shorter, wider bus bars to reduce parasitic inductance and resistance, and a printed circuit board layout that minimizes parasitic inductance and resistance, along with resistors for impedance matching and tuning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If long bus bars are used to connect power devices in parallel, then current capacity is increased, but parasitic inductance and resistance increase leading to ringing and power losses
Solution Approach 1:
The patent transitions from a linear arrangement of power devices connected by long bus bars to a two-dimensional stacked configuration where power devices are arranged in multiple layers. This dimensional change allows current paths to be shortened significantly while maintaining parallel current capacity, as devices in different layers share common bus bar sections, reducing the overall current path length and associated parasitic losses.
Solution Approach 2:
The patent implements a nested structure where power devices are stacked in multiple layers with intermediate bus bars serving multiple functions. The intermediate bus bars act as current collectors for devices in one layer while also serving as connection points for devices in adjacent layers, creating a compact nested arrangement that minimizes external bus bar length and reduces parasitic inductance and resistance.
2Quantity of substance
If long bus bars are used to connect power devices in parallel, then current capacity is increased, but parasitic inductance increases causing ringing
Solution Approach 1:
By arranging power devices in a multi-layer stacked configuration rather than a linear sequence, the patent creates compact current loops with minimal area. This dimensional reorganization dramatically reduces the parasitic inductance of the current paths, thereby suppressing ringing effects while preserving the ability to handle high currents through parallel device operation.
Solution Approach 2:
The patent merges the current paths of multiple parallel power devices by having them share common bus bar sections and connection points. This consolidation of current paths into tighter, overlapping loops reduces the overall parasitic inductance compared to separate long bus bar connections, thereby reducing ringing while maintaining current capacity.
3Loss of energy
If a compact stacked configuration is used for power devices, then parasitic inductance and resistance are reduced, but device complexity increases
Solution Approach 1:
The patent segments the power device assembly into distinct stacked layers with intermediate bus bars serving each layer. This segmentation allows for modular construction and simplified routing of current paths within each layer, making the overall complex configuration more manageable through systematic division into repeating structural units.
Solution Approach 2:
The intermediate bus bars serve multiple functions simultaneously: they act as current collectors for power devices in one layer, provide mechanical support and alignment references for adjacent layers, and serve as connection points for devices in multiple layers. This multi-functionality reduces the total number of separate components needed, simplifying the overall construction despite the three-dimensional arrangement.
Data Source
AI summary
A power drive apparatus is provided. The apparatus includes a first switch having a first plurality of power devices arranged in a back to back configuration within adjacent stacked rows of the first switch. The apparatus includes a second switch having a second plurality of power devices arranged in a back to back configuration within adjacent stacked rows of the second switch. A bus is shared with the first switch and the second switch. The apparatus includes a control drive device coupled to a gate of each power device of the first plurality of power devices and each power device of the second plurality of power devices.