Half-Bridge Converter Parallel LC Filter Ripple Reduction

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Solution Overview

Problem

Electronic converters, particularly half-bridge converters, experience high ripple in output current, which is undesirable for applications like LED lighting where stable current control is necessary.

Innovation Solution

The implementation of a new filter circuit comprising two LC filters connected in parallel, replacing traditional C, LC, or CLC structures, to stabilize the output current and reduce ripple, with specific configurations involving capacitors and inductors connected in series and parallel to improve current regulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If traditional filter circuits (C, LC, or CLC structures) are used in half-bridge converters, then the circuit structure is relatively simple, but high ripple appears in the output current

Engineering Contradiction:
Improveoutput current rippleVSAvoidfilter circuit structure
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The filter circuit is segmented into two separate LC filter branches connected in parallel. Each branch contains an inductor and capacitor combination, dividing the filtering function into multiple independent segments that work together to reduce output current ripple more effectively than a single filter structure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from traditional single-branch filter structures to a two-branch parallel configuration, adding a dimensional aspect to the filter design. This parallel arrangement creates multiple current paths with different impedance characteristics, enabling broader frequency range ripple suppression

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Object-generated harmful factors

If larger output capacitors are used to reduce ripple, then output current stability improves, but component size and cost increase

Engineering Contradiction:
Improveoutput current rippleVSAvoidoutput capacitor size
Core Design Contradiction:
Object-generated harmful factorsVSWeight of stationary object

Solution Approach 1:

The capacitance function is segmented across two parallel branches, each containing capacitors that work in combination. This distribution allows achieving the same or better ripple filtering performance with smaller individual capacitor values, reducing overall component size and cost

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the electrical parameters of the filter circuit by introducing two branches with different L and C values. This parameter optimization enables effective ripple reduction without requiring excessively large capacitor values, thus reducing component size and cost

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

This configuration effectively reduces output current ripple, allowing for more stable voltage and current delivery to LED lighting modules, enabling efficient and controlled brightness adjustment, and potentially reducing the size and cost of output capacitors.

Implementation Method 1

a transformer having a primary winding and a secondary winding

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a rectifier circuit, adapted to convert the current provided through the secondary winding of the transformer into a rectified current

Methodology Applied
Scientific EffectDiode rectification: Diode

Implementation Method 3

A first branch is connected between said two input terminals, wherein said first branch comprises a first inductor and a first capacitor connected in series

Methodology Applied
Scientific EffectInductive impedance: Inductor

Implementation Method 4

a first branch comprises a first inductor and a first capacitor connected in series

Methodology Applied
Scientific EffectCapacitive impedance: Capacitance

Data Source

PatentEP3360240B1Electronic converter and related method of operating an electronic converter
Publication Date: 2021.08.11 OSRAM GMBH
  • EP3360240B1 patent drawingFigure 1~2
  • EP3360240B1 patent drawingFigure 3
  • EP3360240B1 patent drawingFigure 4a~4b

AI summary

There is disclosed an electronic half-bridge converter. The electronic converter (12) comprises an input (110, GND) comprising two terminals for receiving a first power signal (V in ), and an output (106) comprising two terminals for providing a second power signal (V o , i o ). Specifically, the converter comprises a transformer (T) and a half-bridge (S1, S2), wherein the half-bridge (S1, S2) is interposed between input (110, GND) and primary winding (T1) of transformer (T). On the secondary side (T2) of transformer (T), the converter comprises a rectifier circuit (R) configured for converting the current provided via secondary winding (T2) into a rectified current, and a filter circuit (Fa) configured for providing said second power signal (V o , i o ) by means of a filtering of the rectified current provided by rectifier circuit (R). Specifically, the filter circuit (Fa) comprises: - a first branch connected between both input terminals of the filter circuit (Fa) and comprising a first inductor (LF1) and a first capacitor (CF1) connected in series, and - a second branch connected in parallel with the first branch and comprising a second inductor (LF2) and the output (106) connected in series.