Half-Bridge Topology Morphing to Prevent Transformer Core Saturation

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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, employing a morphing operation mode with a frequency multiplier half-bridge configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional on-the-fly topology transition with constant positive voltage pulse length of 50% of pulse period is used, then switching from full-bridge to half-bridge operation is achieved, but magnetizing current increases dynamically causing transformer core saturation

Engineering Contradiction:

Improvetopology transition capabilityVSAvoidtransformer core saturation

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies dynamics by making the positive inverter voltage pulse length variable rather than constant. The pulse length is dynamically adjusted based on the negative inverter voltage pulse length to maintain proper magnetizing current levels during topology transitions, preventing transformer core saturation while enabling smooth operation mode changes.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of positive voltage pulse length from a fixed 50% of pulse period to a variable parameter determined by the negative inverter voltage pulse length. This parameter adjustment ensures that the magnetizing current remains within safe limits during morphing operations, resolving the saturation issue while maintaining transition capability.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If duty cycles of half-bridge switches are adjusted to change from 50% to 0% for one switch during morphing, then oscillations of output are reduced significantly, but partial saturation of transformer core occurs due to dynamic increase of magnetizing current

Engineering Contradiction:

Improveoutput oscillation reductionVSAvoidtransformer core partial saturation

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent implements feedback by using the negative inverter voltage pulse length as a reference to determine the positive inverter voltage pulse length during morphing operations. This feedback mechanism ensures that the magnetizing current is kept within acceptable limits while achieving smooth output transitions, thus preventing both excessive oscillations and transformer core saturation.

Inventive Principle:

Principle #23Feedback

3Object-affected harmful factors

If positive inverter voltage pulse length is dynamically adjusted based on negative inverter voltage pulse length, then dynamic increase of magnetizing current is limited to prevent transformer saturation, but control complexity increases

Engineering Contradiction:

Improvetransformer saturation preventionVSAvoidcontrol circuit complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent uses the negative inverter voltage pulse length as an intermediary parameter to control the positive inverter voltage pulse length. This intermediary approach provides a straightforward control relationship that prevents transformer saturation without requiring complex control algorithms, thus balancing protection capability with control simplicity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20260012099A1On-the-fly topology morphing for frequency-multiplier half-bridge operation

Publication Date: 2026.01.08 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.