Power Module Insulation Segmentation for EMI Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In power conversion apparatuses with integrated rectifier and inverter portions on a single metal substrate, capacitive coupling generates capacitance that reduces the effectiveness of noise filters, leading to inadequate electromagnetic interference (EMI) reduction.
Innovation Solution
The power module's insulating layer and aluminum base are electrically isolated between the rectifier and inverter semiconductor chips, with the separation covered by plastic to maintain insulation, reducing capacitance and enhancing noise filter efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the rectifier portion and inverter portion are mounted on the same metal substrate within a single power module, then the device complexity is reduced and integration is improved, but capacitive coupling is generated through the metal substrate which reduces the effectiveness of noise filters
Solution Approach 1:
The power module is divided into two electrically isolated parts: a first part containing the rectifier portion and a second part containing the inverter portion. The metal substrate is correspondingly divided into a first substrate and a second substrate, which are electrically isolated from each other. This segmentation prevents capacitive coupling between the rectifier and inverter portions while maintaining integration within a single module structure.
Solution Approach 2:
An insulating layer is introduced as an intermediary between the first substrate and the second substrate. This insulating layer electrically isolates the two substrates, preventing the generation of capacitive coupling and its associated harmful effects on noise filter effectiveness, while still allowing the power module to maintain a compact integrated structure.
2Object-affected harmful factors
If a noise filter is mounted in the power module to reduce electromagnetic interference, then the EMI reduction effect is improved, but the capacitance generated by capacitive coupling through the metal substrate reduces the filter effectiveness
Solution Approach 1:
By segmenting the metal substrate into electrically isolated first and second substrates, the capacitive coupling path that degrades noise filter effectiveness is eliminated. This allows the noise filter to function at its full designed effectiveness without being compromised by parasitic capacitance.
3Object-affected harmful factors
If the insulating layer and aluminum base are divided into two electrically isolated parts, then the capacitance is reduced and noise filter effectiveness is improved, but the manufacturing complexity increases
Solution Approach 1:
The division of the metal substrate into electrically isolated first and second substrates, along with the insulating layer, creates a modular structure that can be manufactured using standard PCB fabrication techniques. The segmentation is achieved through conventional insulating layer deposition and substrate separation processes, making the manufacturing complexity manageable.
Solution Approach 2:
The insulating layer serves as an intermediary that enables electrical isolation between the first and second substrates. This insulating layer can be applied using standard manufacturing techniques such as lamination or deposition, making the isolation process compatible with existing power module fabrication workflows.
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 significantly improves the noise reduction effect by minimizing capacitive coupling, achieving a 15 dB or more quasi-peak (QP) value improvement in EMI levels, maintaining filter effectiveness even when the coil is arranged within the power module.
Implementation Method 1
a capacitive coupling may be generated through metal plates including a substrate, an underlying aluminum base (hereinafter referred to as the aluminum base) and a conductor between the ends (input and output units) of the coil arranged in the power module as a circuit element to reduce EMi
Data Source
AI summary
A power conversion apparatus is disclosed. In the case where a coil is arranged in a power module, the circuit system between the ends of the coil in the power module, regardless of where the coil is located, is structurally isolated and insulated from each other. This isolation and insulation prevents the capacitance from being created across the coil, and the coil can exhibits the effect as a filter, thereby improving the characteristics of a noise filter.