Interleaving Busbar Layout for Low-Inductance Power Modules
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Solution Overview
Problem
Existing power modules with third-generation semiconductors suffer from significant parasitic inductance issues, leading to signal distortion, efficiency degradation, and instability under high-frequency, high-current conditions, particularly in applications like electric vehicle motors, due to inadequate design of current inflow-outflow paths.
Innovation Solution
A low parasitic inductance power module design featuring staggered, interleaving busbars with interdigitated contact terminals that cancel individual inductances, ensuring homogeneous current distribution and reduced parasitic inductance through interleaving configurations in both width and height directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional busbar layout is used, then manufacturing is simple, but parasitic inductance is high causing signal distortion and efficiency degradation
Solution Approach 1:
The busbars are segmented into multiple sections with interdigitated contact terminals instead of using continuous straight busbars. This segmentation allows the current paths to be divided into multiple smaller loops, reducing the overall parasitic inductance while maintaining manufacturability through modular construction
Solution Approach 2:
The busbar layout transitions from a conventional planar arrangement to a three-dimensional staggered interleaving configuration. The contact terminals are arranged in alternating patterns across multiple levels, creating overlapping current loops that cancel magnetic fields and reduce parasitic inductance
2Object-affected harmful factors
If busbars are placed close to power devices, then parasitic inductance is reduced, but bonding zone availability is limited
Solution Approach 1:
The solution moves from a two-dimensional planar layout to a three-dimensional staggered arrangement where contact terminals are distributed across multiple levels. This vertical dimensionality allows bonding zones to be positioned optimally close to power devices while maintaining adequate space for interdigitated terminal arrangements
Solution Approach 2:
The interdigitated contact terminals are nested in an alternating pattern between input and output busbars, with terminals of one busbar interleaved with terminals of the other. This nested arrangement maximizes the use of available bonding zone area while minimizing the loop area and parasitic inductance
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
The design effectively reduces overall parasitic inductance to below 5 nH, enhancing stability and efficiency by cancelling induced magnetic fields, facilitating high-frequency and high-current operations without signal distortion.
Implementation Method 1
According to Ampere's Law, in an AC circuit, a time-varying magnetic field is created when electric current travels through a wire or a power component, while according to Faraday's Law and Lenz's Law, the time-varying magnetic field in turn creates an opposing induced electromotive force that influences the current signal. This effect, due to its analogousness to inductance, is usually referred to as 'parasitic inductance' or 'stray inductance'
Implementation Method 2
the interdigitated contact terminals of the current input busbar and the interdigitated contact terminals of the current output busbar which generate mutually cancelled individual inductances when current flows therethrough
Data Source
AI summary
A low parasitic inductance power module having staggered, interleaving busbars, including: at least one base extending a long a length direction, the base having at least one current input busbar and at least one current output busbar, the current input busbar and the current out busbar being formed with a plurality of interdigitated contact terminals, respectively; a first unit comprising a first circuit base portion disposed on the base along the width direction, on the first circuit base portion being disposed a plurality of first power devices; and a second unit, whereby when current flows through the units and the individual interdigitated contact terminals, individual inductances produced thereby are cancelled with each other, whereby overall parasitic inductance of the power module is reduced.