High Power Factor Converter with Segmented Capacitors

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Solution Overview

Problem

Conventional flyback converters require large output capacitors to achieve low output voltage ripple, making them impractical due to size and implementation challenges, while also struggling to maintain high power factor.

Innovation Solution

A high power factor converter design incorporating an EMI filter, reactive power control circuit, and converter circuit with a transformer and switch, which uses reactive power control capacitors and diodes to manage energy storage and release, thereby reducing the need for large capacitors and minimizing secondary ripple.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a large output capacitor is used to reduce output voltage ripple, then the output voltage ripple is reduced, but the device size and implementation complexity increase

Engineering Contradiction:

Improveoutput voltage rippleVSAvoidoutput capacitor size

Core Design Contradiction:

Stability of the object's compositionVSVolume of stationary object

Solution Approach 1:

The patent divides the output capacitor into two separate capacitors: a first output capacitor connected to the secondary winding and a second output capacitor connected to the output terminal. This segmentation allows each capacitor to be smaller while collectively achieving the required ripple reduction, thus resolving the contradiction between ripple performance and capacitor size.

Inventive Principle:

Principle #1Segmentation

2Stability of the object's composition

If a large output capacitor is used to reduce output voltage ripple, then the output voltage ripple is reduced, but the device complexity increases

Engineering Contradiction:

Improveoutput voltage rippleVSAvoidcapacitor configuration complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent segments the output capacitor into two capacitors with distinct functions, which simplifies the overall circuit design by allowing each capacitor to be optimized independently rather than requiring one large capacitor, thus reducing implementation complexity.

Inventive Principle:

Principle #1Segmentation

3Device complexity

If conventional flyback converter topology is used, then the circuit structure is simple, but the power factor is low

Engineering Contradiction:

Improveconverter circuit structureVSAvoidpower factor

Core Design Contradiction:

Device complexityVSEase of manufacture

Solution Approach 1:

The patent combines the PFC function and flyback conversion function into a single integrated circuit structure. The first output capacitor is connected in parallel with the secondary winding while the second output capacitor is connected to the output terminal, merging the PFC and flyback stages into one unified design that achieves both high power factor and simplified structure.

Inventive Principle:

Principle #5Merging (Combining)

4Device complexity

If conventional flyback converter topology is used, then the circuit structure is simple, but the power factor is low

Engineering Contradiction:

Improveconverter circuit structureVSAvoidpower factor

Core Design Contradiction:

Device complexityVSUse of energy by moving object

Solution Approach 1:

The patent merges the PFC and flyback conversion functions into a single integrated topology, where the first output capacitor enables PFC operation to improve power factor while the second output capacitor maintains the flyback output function, achieving high energy efficiency without increasing structural complexity.

Inventive Principle:

Principle #5Merging (Combining)

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 solution achieves high power factor and low output voltage ripple without the necessity of large output capacitors, ensuring efficient energy transfer and reduced secondary ripple, as demonstrated by experimental results showing a power factor of 0.952 and low frequency ripple elimination.

Implementation Method 1

an electromagnetic interference (EMI) filter for filtering and suppressing EMI noise for the input AC voltage

Methodology Applied

Scientific EffectElectromagnetic filtering: Filter (electronic)

Implementation Method 2

a reactive power control capacitor, wherein a first terminal of the reactive power control capacitor is coupled to the second terminal of the second inductor and a second terminal of the reactive power control capacitor is coupled to the anode of the first diode

Methodology Applied

Scientific EffectCapacitive energy storage: Capacitance

Implementation Method 3

a transformer comprising a primary winding and a secondary winding

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS10476376B1High power factor converter

Publication Date: 2019.11.12 NAT CHUNG SHAN INST SCI & TECH

AI summary

A high power factor converter is provided. The high power factor converter includes a rectifier, a reactive power control circuit and a converter circuit. The rectifier is utilized for receiving and converting an input AC voltage in to an input DC voltage. The reactive power control circuit is coupled to the rectifier for performing a reactive power control operation based on the input DC voltage. The converter circuit is coupled to the reactive power control circuit for converting the input DC voltage into an output voltage.