Integrated AC Line Filter Rectifier Module with Metal Heat Sink

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Solution Overview

Problem

Conventional AC line filter modules and full-wave bridge rectifiers require separate components and incur additional costs for heat sinking and tooling due to the need for four diodes and two two-winding inductors, which are physically large and expensive to produce.

Innovation Solution

An integrated AC Line Filter/Rectifier Module (ACLF/RM) that combines EMI filtering and rectification using four low forward voltage rectifiers with two two-winding inductors, where the metal housing serves both as an EMI shield and a heat sink, eliminating the need for external heat sinks and reducing tooling costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate conventional AC line filter module and full-wave bridge rectifier are provided, then EMI filtering and rectification functions are achieved, but cost increases due to additional heat sinking and tooling requirements

Engineering Contradiction:

ImproveEMI filtering and rectification functionVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines the AC line filter module and full-wave bridge rectifier into a single integrated module. The metal housing that traditionally only provided EMI shielding now also serves as a heat sink for the rectifier diodes, eliminating the need for separate heat sinking components and reducing manufacturing complexity

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The metal housing is designed to perform multiple functions simultaneously: it provides EMI shielding for the filter circuitry and acts as a heat sink for the rectifier diodes. This multi-functionality reduces the overall component count and manufacturing cost while maintaining both filtering and thermal management functions

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If four diodes and two two-winding inductors are used in separate modules, then rectification and filtering are achieved, but device complexity and component count increase

Engineering Contradiction:

Improverectification and filtering performanceVSAvoidcomponent count

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent integrates the filter inductors and rectifier diodes into a single module housing, reducing the number of discrete components and interconnections required. The two two-winding inductors serve dual purposes in the filter circuit while the four diodes are arranged in a bridge configuration that shares common mounting structures

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If conventional diodes are used in full-wave bridge rectifier, then rectification function is achieved, but forward voltage drop and energy loss increase

Engineering Contradiction:

Improverectification functionVSAvoidforward voltage loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent specifies using fast recovery diodes with optimized forward voltage characteristics in the bridge rectifier configuration. By carefully selecting diodes with appropriate forward voltage drops and recovery times, the design achieves efficient rectification while minimizing power losses during the switching transitions

Inventive Principle:

Principle #35Parameter changes

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 ACLF/RM achieves efficient AC-to-DC rectification with reduced costs and heat dissipation, maintaining high energy efficiency and performance comparable to separate modules, while integrating functions and reducing component count.

Implementation Method 1

two two-winding inductors (also referred to as transformers). These two two-winding inductors are coupled to the bipolar transistors of the low forward voltage rectifiers and perform current-splitting

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the metal housing of the ACLF/RM performs both its EMI shielding and suppression function (as in a conventional AC line filter module) as well an additional heat sinking function for an AC-to-DC rectifier

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

The rectification circuitry includes at least one low forward voltage rectifier, where the low forward voltage rectifier includes a bipolar transistor and a diode

Methodology Applied

Scientific EffectDiode rectification: Diode

Data Source

PatentUS9923324B2AC line filter and AC-to-DC rectifier module

Publication Date: 2018.03.20 LITTELFUSE INC

AI summary

An AC Line Filter/Rectifier Module (ACLF/RM) has a metal housing and an outward appearance of a conventional AC line filter, but the ACLF/RM includes circuitry that performs both EMI filtering and line filtering as well as very efficient AC-to-DC rectification. Rectification circuitry within the ACLF/RM rectifies an AC voltage signal received onto AC input module terminals and outputs a rectified version of the AC voltage signal onto DC output module terminals. The rectification circuitry includes at least one low forward voltage rectifier, where the low forward voltage rectifier includes a bipolar transistor and a diode. Inductive components perform both EMI filtering and line filtering as well as current splitting required to drive the bipolar transistors of the low forward voltage rectifiers. Due to the use of the low forward voltage rectifiers, the AC-to-DC conversion is more efficient than would be case were a conventional diode bridge rectifier employed.