Power Conversion Circuit Layout for Smaller Common-Mode Inductors
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Solution Overview
Problem
High-power power supply adapters face significant losses and size issues due to large common-mode inductors, which increase input current and reduce efficiency, especially when operating across varying AC input voltages from 90 Vac to 264 Vac, and existing solutions like larger magnet rings and thicker wires result in larger inductors that hinder high power density and efficiency.
Innovation Solution
A power conversion circuit design that relocates the common-mode inductor from the AC side to the DC side, connecting its terminals to the AC/DC conversion circuit and DC/DC conversion circuit respectively, with reference potential points connected to an electric field shield, such as a metal shielding layer, to reduce power loss and size without compromising electromagnetic interference filtering performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a common-mode inductor with large magnet ring and thick wire is used to reduce power loss, then power loss is reduced, but the size of the common-mode inductor becomes large
Solution Approach 1:
The patent changes the operating parameters by relocating the common-mode inductor from the AC input side to the DC side after rectification. This parameter change allows the inductor to operate at lower current levels, enabling the use of smaller magnet rings and thinner wires while maintaining acceptable power loss performance.
Solution Approach 2:
The patent transitions the common-mode inductor from a three-phase AC current environment to a single-phase DC environment, fundamentally changing the dimensional characteristics of the current it handles. This dimensional change from handling high AC input current to handling lower DC current enables significant size reduction of the inductor components.
2Object-affected harmful factors
If the common-mode inductor is placed on the AC side to filter electromagnetic interference, then EMI filtering performance is improved, but power loss and inductor size increase
Solution Approach 1:
The patent introduces the rectifier circuit as an intermediary between the AC input and the common-mode inductor. By placing the inductor on the DC side after rectification, the rectifier acts as a mediator that converts the high-current AC signal to a lower-current DC signal, allowing the inductor to perform EMI filtering with reduced power loss and smaller size.
Solution Approach 2:
The patent moves the common-mode inductor from the AC time dimension to the DC time dimension, where the current characteristics are fundamentally different. This dimensional transition allows the inductor to achieve EMI filtering performance while operating at lower current levels, reducing both power loss and physical size.
3Object-affected harmful factors
If the common-mode inductor is placed on the AC side to suppress common-mode noise, then noise suppression is improved, but input current increases and efficiency decreases
Solution Approach 1:
The patent changes the current parameter from high-level AC input current to lower-level DC current by relocating the common-mode inductor to the DC side. This parameter change maintains noise suppression capability while reducing the current through the inductor, thereby improving overall system efficiency.
Solution Approach 2:
The patent extracts the common-mode inductor from the AC input stage and places it in the DC stage, separating the rectification function from the EMI filtering function. This extraction allows each component to operate in its optimal environment, with the inductor handling lower DC currents for improved efficiency while still providing necessary noise suppression.
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 design significantly reduces power loss and inductor size, enhancing power density and efficiency while maintaining effective electromagnetic interference filtering, with power loss reduced to 1/16 to 1/25 of the original and allowing for smaller magnet rings and thinner wires.
Implementation Method 1
the first reference potential point or the second reference potential point is connected to an electric field shield
Implementation Method 2
the common-mode filter includes a common-mode inductor, i.e., a common-mode choke, which is often applied to filter common-mode electromagnetic interference signals to suppress common-mode noise
Data Source
AI summary
The invention discloses a power conversion circuit and a power supply device. The power conversion circuit is applied to a power supply device, comprising: an AC/DC conversion circuit, wherein a DC side of the AC/DC conversion circuit has a first reference potential point; a first common-mode inductor; a DC/DC conversion circuit including a primary circuit having a second reference potential point, a secondary circuit and a transformer; wherein a first terminal of the first common-mode inductor is connected to the DC side of the AC/DC conversion circuit, and a second terminal of the first common-mode inductor is connected to the primary circuit of the DC/DC conversion circuit; the first reference potential point or the second reference potential point is connected to an electric field shield.