Integrated PFC Inductor Layout for Common-Mode Noise Suppression
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Solution Overview
Problem
The challenge of suppressing common-mode noise in switch-mode power supplies with high switching frequencies is exacerbated by the limited board area available for common-mode inductors, which are necessary to reduce harmonic content and improve power factor.
Innovation Solution
An integrated inductor design with M+1 magnetic yokes and S windings arranged in parallel on a printed circuit board, where S first and S second windings occupy overlapping positions, reducing board area and material costs while effectively suppressing common-mode noise and optimizing electromagnetic interference (EMI).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a large common-mode inductance is required in the common-mode filter network, then common-mode noise suppression is improved, but the occupied board area increases
Solution Approach 1:
The patent combines multiple inductors (first inductor and second inductor) into a single integrated inductor structure with shared magnetic core and winding arrangements. This merging allows the circuit to achieve the required common-mode inductance while occupying significantly less board area than discrete inductors would require.
Solution Approach 2:
The patent utilizes three-dimensional space by stacking magnetic cores and arranging windings in multiple layers and orientations. The integrated inductor employs vertical stacking of magnetic cores and multi-layer PCB windings, transforming the inductance generation from a two-dimensional planar layout to a three-dimensional structure, thereby reducing the footprint on the board.
2Object-affected harmful factors
If discrete inductors are used to provide common-mode inductance, then noise suppression is achieved, but material costs and device complexity increase
Solution Approach 1:
The patent merges multiple inductor functions into a single integrated component that contains both the first inductor and second inductor windings within one magnetic core structure. This reduces the total component count, simplifies the circuit layout, and lowers material costs compared to using separate discrete inductors.
Solution Approach 2:
The integrated inductor structure serves multiple functions simultaneously: it provides common-mode inductance for noise filtering, enables power factor correction through its winding configurations, and reduces overall circuit complexity. This multi-functional design eliminates the need for separate components for each function.
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 integrated inductor design achieves reduced board area, lower material costs, and improved power density by effectively suppressing common-mode noise and optimizing EMI in power factor correction circuits.
Implementation Method 1
The integrated inductor includes a magnetic core, S first windings, and S second windings
Data Source
AI summary
One example power factor correction (PFC) circuit includes S first bridge arms, a second bridge arm, and a voltage stabilization capacitor that are connected in parallel, and the PFC circuit further includes an integrated inductor. The integrated inductor includes a magnetic core, S first windings, and S second windings. Second ends of the S first windings are respectively connected to midpoints of the S first bridge arms. A second end of a balancing unit formed by the S second windings are connected to a midpoint of the second bridge arm. The magnetic core includes M+1 first magnetic yokes sequentially arranged in parallel. The S first windings and the S second windings are disposed in spaces formed by any two adjacent first magnetic yokes. Two adjacent first magnetic yokes corresponding to the S first windings are the same, and two adjacent first magnetic yokes corresponding to the S second windings are the same.