Flyback Converter Surge Power Control via Dynamic Frequency

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Solution Overview

Problem

Conventional flyback converters struggle to deliver surge power without increasing cost, as they often require larger transformers to avoid saturation, and lack effective short-circuit protection mechanisms.

Innovation Solution

The method involves a flyback converter circuit with a transformer, where the controller adjusts the switching frequency and current limit of the primary current based on feedback voltage to increase power delivery during surge conditions, while also implementing adaptive control schemes to prevent core saturation and short-circuit damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the transformer size is increased to avoid core saturation during surge load, then the power delivery capability is improved, but the cost and device size increase

Engineering Contradiction:
Improvepower delivery capabilityVSAvoidtransformer size
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the switching frequency adjustable rather than fixed. The controller dynamically changes the switching frequency based on load conditions - operating at lower frequencies during normal load to reduce losses and at higher frequencies during surge load to increase power delivery capability. This dynamic adjustment allows the converter to meet surge power demands without requiring a larger transformer.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the operating parameter (switching frequency) to resolve the contradiction. By varying the switching frequency within a controlled range, the converter can deliver excess power during surge conditions without saturating the transformer core, thereby avoiding the need for a larger transformer while maintaining cost-effectiveness.

Inventive Principle:
Principle #35Parameter changes

2Power

If the switching frequency is increased during surge load, then the power delivery capability is improved, but the switching loss increases

Engineering Contradiction:
Improvepower delivery capabilityVSAvoidswitching loss
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The controller dynamically adjusts the switching frequency based on real-time load conditions. During normal operation, the converter operates at a lower switching frequency to minimize switching losses and maximize efficiency. When surge load is detected, the controller increases the switching frequency to boost power delivery capability. This dynamic adaptation allows the system to optimize the trade-off between power delivery and switching loss under different operating conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs periodic monitoring of load conditions and adjusts the switching frequency in response to detected surge demands. The controller continuously monitors the output voltage and current, and periodically modifies the switching frequency to match the power delivery requirements, thereby managing switching losses effectively while maintaining the ability to deliver surge power when needed.

Inventive Principle:
Principle #19Periodic action

3Power

If the primary peak current limitation is increased during surge load, then the power delivery capability is improved, but the risk of short circuit damage increases

Engineering Contradiction:
Improvepower delivery capabilityVSAvoidshort circuit protection
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent implements feedback control by continuously monitoring the output voltage and current, and using this information to adjust the primary peak current limitation dynamically. During surge load conditions, the controller temporarily increases the current limitation to enable higher power delivery. However, the feedback mechanism continuously monitors system parameters and automatically reduces the current limitation when normal conditions return or when abnormal conditions (such as short circuit) are detected, thereby maintaining reliability and preventing damage.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The primary peak current limitation is made dynamic rather than fixed. The controller adapts the current limitation based on load conditions - allowing higher current during verified surge demands while maintaining lower limitations during normal operation. This dynamic adjustment, combined with continuous monitoring, enables the system to deliver surge power when needed while maintaining protection against short circuit damage through automatic parameter adaptation.

Inventive Principle:
Principle #15Dynamics

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 approach allows for efficient power delivery during surge conditions without the need for costly transformer upgrades and provides effective short-circuit protection, ensuring reliable operation and preventing damage to the converter.

Implementation Method 1

a transformer, where the controller adjusts the switching frequency and current limit of the primary current

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2731247B1Method for flyback converter
Publication Date: 2021.03.17 DELTA ELECTRONICS INC(CN)
  • EP2731247B1 patent drawingFigure 1
  • EP2731247B1 patent drawingFigure 2
  • EP2731247B1 patent drawingFigure 3

AI summary

Methods for flyback converters are provided. The method, adopted by a flyback converter circuit including a transformer, including: determining an output voltage output from a secondary circuit of the transformer; feeding a feedback voltage based on the output voltage from the secondary circuit back to a primary circuit of the transformer; increasing a current limit and a switching frequency of a primary current with the feedback voltage; and supplying the primary current to a primary winding of the transformer.