Power Converter Filter Circuit Resonance Noise Suppression
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Solution Overview
Problem
High-frequency switching noise in power converter apparatuses is amplified by resonance phenomena due to parasitic inductance between bypass capacitors, leading to malfunction and inefficiency, especially as next-generation devices operate at higher frequencies.
Innovation Solution
A power converter apparatus with a filter circuit comprising first and second bypass capacitors and inductors, where the inductance is set to ensure a resonance frequency lower than the switching frequency, thereby reducing switching noise and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If bypass capacitors are connected with small inductance to operate in high frequency region, then switching noise is reduced, but resonance phenomenon occurs due to parasitic inductance
Solution Approach 1:
The patent changes the inductance parameter of the bypass inductor to a specific range (0.1 μH to 10 μH) to adjust the resonance frequency below the switching frequency, thereby preventing resonance amplification while maintaining high-frequency operation capability
Solution Approach 2:
The patent introduces a bypass inductor as an intermediary element between the high-frequency bypass capacitor and low-frequency bypass capacitor, which acts as a damping element to suppress resonance phenomenon caused by parasitic inductance in the wiring
2Object-generated harmful factors
If inductance is increased to reduce resonance, then switching noise is suppressed, but circuit complexity increases
Solution Approach 1:
The patent combines the bypass inductor with existing bypass capacitors to form an integrated filter circuit that suppresses switching noise across multiple frequency ranges, achieving noise suppression without requiring separate complex filter stages
3Productivity
If next-generation power devices operate at higher frequencies, then power conversion efficiency is improved, but switching noise level increases
Solution Approach 1:
The patent segments the noise suppression function into two frequency ranges: high-frequency noise (100 MHz to a few 100 MHz) suppressed by the high-frequency bypass capacitor, and low-frequency switching noise suppressed by the low-frequency bypass capacitor, with the bypass inductor coordinating both stages
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 reduces switching noise, simplifies the circuit, and enhances operational efficiency by avoiding resonance amplification and overcurrent issues, even at higher frequencies.
Implementation Method 1
a resonance phenomenon occurs due to these LC circuits
Implementation Method 2
The inductance (L) of the inductor is set so that a resonance frequency (fr) of the filter circuit is lower than the switching frequency (fSW)
Implementation Method 3
the filter circuit converts the AC voltage from the switching circuit into a DC voltage by low-pass filtering the AC voltage
Implementation Method 4
The first bypass capacitor bypasses noise of a first frequency component of the AC voltage from the switching circuit, and the second bypass capacitor bypasses noise of a second frequency component
Data Source
AI summary
A power converter apparatus is provided to include a switching circuit, and a filter circuit. The switching circuit generates an AC voltage by switching a DC voltage at a predetermining switching frequency, and the filter circuit converts the AC voltage from the switching circuit into the DC voltage by low-pass filtering the AC voltage. The filter circuit induces first and second bypass capacitors, and an inductor. The first bypass capacitor bypasses noise of a first frequency component of the AC voltage from the switching circuit, and the second bypass capacitor bypasses noise of a second frequency component of the AC voltage from the switching circuit, which is lower than the first frequency component. The inductor is inserted between the first and second bypass capacitors, and the inductance thereof is set so that a resonance frequency of the filter circuit is lower than the switching frequency by insertion of the inductor.