Semiconductor Module Bus Bar Layout for EMI and Electrostatic Shielding
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Solution Overview
Problem
Existing semiconductor modules face issues with magnetic noise and electrostatic noise due to adjacent electrically conductive layers with different potentials, which can cause malfunctions when current or potential changes occur.
Innovation Solution
The semiconductor module incorporates a configuration where a first bus bar serially connects semiconductor switching elements in each leg of an inverter circuit and a second bus bar, connected to the low potential side, is disposed between the first bus bar and the circuit board, with overlapping bus bars having opposite current directions, acting as an electromagnetic and electrostatic shield to suppress noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrically conductive layers with different potentials are disposed adjacently to enable current flow, then electrical connectivity is achieved, but magnetic noise and electrostatic noise are generated causing malfunctions
Solution Approach 1:
An insulating layer is introduced as an intermediary between electrically conductive layers with different potentials. This insulating layer physically separates the conductive layers while maintaining electrical connectivity through controlled connection points, thereby preventing direct electromagnetic coupling and reducing magnetic noise and electrostatic noise interference.
Solution Approach 2:
The harmful electromagnetic interaction between adjacent conductive layers is extracted and eliminated by inserting the insulating layer. This separation removes the source of magnetic noise and electrostatic noise generation while preserving the necessary electrical connectivity through designated connection paths.
2Reliability
If bus bars are disposed to connect semiconductor switching elements, then electrical connectivity is achieved, but electromagnetic interference occurs between overlapping bus bars
Solution Approach 1:
An insulating layer is positioned between overlapping bus bars to act as an electromagnetic shield and physical separator. This intermediary layer prevents direct electromagnetic coupling between the bus bars carrying different potentials, reducing electromagnetic interference while maintaining the electrical connectivity function of the bus bars.
Solution Approach 2:
The overlapping configuration of bus bars, which inherently causes electromagnetic interference, is transformed into a beneficial arrangement by introducing the insulating layer. The insulating layer converts the harmful electromagnetic coupling into isolated electrical paths, allowing the overlapping structure to maintain compactness while eliminating interference.
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 configuration effectively prevents magnetic and electrostatic noise from influencing the circuit board, thereby suppressing malfunctions caused by current or potential changes in the semiconductor module.
Implementation Method 1
the direction of a current flowing through the first bus bar is opposite to the direction of a current flowing through the second bus bar
Implementation Method 2
a second bus bar that is connected to a high potential side or a low potential side of the leg and disposed between the first bus bar and the circuit board
Data Source
AI summary
A semiconductor module includes a circuit board, semiconductor switching elements for an inverter circuit connected to the circuit board, bus bars, and a mold integrally sealing the circuit board, the semiconductor switching elements, and the bus bars. The switching elements are disposed in a plane direction of the circuit board. The bus bars include a first bus bar serially connecting the switching elements in each leg of the inverter circuit to each other and a second bus bar connected to a high potential side or a low potential side of the leg and disposed between the first bus bar and the circuit board. The first bus bar and the second bus bar at least partly overlap. The direction of a current flowing through the first bus bar is opposite to the direction of a current flowing through the second bus bar.