Full-Bridge Topology Morphing for Transformer Saturation Control

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Solution Overview

Problem

Conventional on-the-fly topology transitions in full-bridge converters lead to dynamic increases in magnetizing current, causing transformer core saturation during mode changes.

Innovation Solution

A full bridge converter-circuit with a H-bridge that dynamically adjusts positive and negative inverter voltage pulse lengths using a control circuit to limit magnetizing current increases during mode transitions, employing a lookup table for fast and reliable duty cycle determination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If constant duty cycle of 50% is used during topology transition, then output oscillations are reduced, but magnetizing current increases dynamically causing transformer core saturation

Engineering Contradiction:

Improveoutput oscillation reductionVSAvoidtransformer core saturation

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent applies dynamics by transitioning from constant duty cycle to dynamic duty cycle adjustment during topology morphing. The duty cycle of the first half-bridge is varied continuously from 50% to 0% (or 100%) while the second half-bridge duty cycle is adjusted complementarily, enabling smooth transition without magnetizing current spikes that would cause saturation.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the duty cycle parameter dynamically during the transition process. By adjusting the duty cycle of the first half-bridge switches from 50% to 0% (or 100%) and simultaneously adjusting the second half-bridge duty cycle, the magnetizing current is controlled to prevent saturation while maintaining stable output.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If duty cycle of first half-bridge is adjusted from 50% to 0% during morphing, then transformer saturation is prevented, but transition smoothness may be affected

Engineering Contradiction:

Improvemagnetizing current controlVSAvoidtransition smoothness

Core Design Contradiction:

Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The patent ensures continuity of useful action by continuously adjusting both half-bridge duty cycles during the morphing process. The first half-bridge duty cycle transitions continuously from 50% to 0% (or 100%) while the second half-bridge duty cycle transitions complementarily, maintaining continuous control over the magnetizing current and ensuring smooth transition without discontinuities or abrupt changes.

Inventive Principle:

Principle #20Continuity of useful action

3Power

If frequency multiplier half bridge operation is used, then voltage-transfer ratio is increased, but thermal imbalances may occur

Engineering Contradiction:

Improvevoltage-transfer ratioVSAvoidjunction temperature imbalance

Core Design Contradiction:

PowerVSTemperature

Solution Approach 1:

The patent applies local quality by enabling frequency multiplier half-bridge operation in specific operating conditions while maintaining full-bridge operation in others. The controller dynamically selects the operation mode based on load requirements, allowing the system to achieve high voltage-transfer ratio when needed while avoiding thermal imbalances by switching to full-bridge mode when appropriate.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS12456927B2On-the-fly topology morphing for frequency-multiplier half-bridge operation

Publication Date: 2025.10.28 DELTA ELECTRONICS (THAILAND) PUBLIC CO LTD

AI summary

Full bridge converter-circuit having a H-bridge, comprising a control circuit for operating the H-bridge in a first operation mode or a second operation mode, wherein the control circuit is configured that between switching from the first operation mode to the second operation mode a morphing operation mode is applied in which a positive inverter voltage pulse length on a first half-bridge of the H-bridge is determined on the basis of a negative inverter voltage pulse length on a second half-bridge of the H-bridge.