Power Module Parasitic Inductance Damping for EMI Noise Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In power modules, high-frequency oscillations between switching elements lead to elevated radiation noise, which complicates manufacturing and fails to meet electromagnetic interference (EMI) regulations due to differing parasitic inductances and switching characteristics of elements connected in series.
Innovation Solution
A power module design that includes additional wiring directly connecting switching elements, which alters parasitic inductances and switching characteristics, thereby reducing high-frequency oscillations and radiation noise by shifting the frequency band out of regulatory ranges and converting oscillation energy into Joule heat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a plurality of switching elements are connected in series to increase capacity, then the required power capacity is achieved, but high-frequency oscillation occurs due to differences in parasitic inductances and switching characteristics, leading to elevated radiation noise
Solution Approach 1:
The patent introduces a damping resistor to change the electrical parameters of the circuit, specifically adding resistance to dampen high-frequency oscillations. This parameter change suppresses the oscillation caused by differences in parasitic inductances between parallel switching elements, thereby reducing radiation noise while maintaining the required power capacity
Solution Approach 2:
The patent converts the harmful high-frequency oscillation energy into heat through the damping resistor. By intentionally introducing a resistive element, the oscillation energy that would otherwise radiate as electromagnetic noise is dissipated as Joule heat, transforming a harmful effect into a controlled energy dissipation mechanism
2Power
If the element size is increased to meet capacity requirements, then the power capacity is sufficient, but the yield is lowered and manufacturing becomes difficult
Solution Approach 1:
The patent divides the power module into multiple parallel switching elements instead of using a single large element. This segmentation allows each element to remain within manufacturable size limits while achieving the required total power capacity through parallel connection, thereby maintaining high yield and ease of manufacturing
3Power
If parallel switching elements with different parasitic inductances are used, then the power capacity is achieved, but high-frequency oscillation occurs between the elements
Solution Approach 1:
The damping resistor acts as an intermediary element between the parallel switching elements. It mediates the interaction between elements with different parasitic inductances by providing a common resistive path that equalizes the oscillation tendencies, thereby stabilizing the switching behavior without requiring all elements to have identical electrical characteristics
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 solution effectively reduces radiation noise by attenuating high-frequency oscillations and ensuring compliance with EMI standards, allowing for smaller element sizes and improved manufacturing efficiency.
Implementation Method 1
parasitic inductances of the first and second wiring are different
Implementation Method 2
converting oscillation energy into Joule heat
Data Source
AI summary
A power module comprises: first and second terminals; first and second switching elements having a first electrode and a second electrode which is connected to the second terminal; first and second wirings respectively connecting the first electrodes of the first and second switching elements to the first terminal; and a third wiring directly connecting the first electrode of the first switching element to the first electrode of the second switching element, wherein parasitic inductances of the first and second wiring are different or switching characteristics of the first and second switching elements are different.