Transformer Bias Compensation in DC-DC Converter Duty Control

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Solution Overview

Problem

Long-time operation of DC-DC converters in power electronics leads to bias magnet issues in transformers due to differences in switching speeds and drive signal delays, which existing solutions like adding a DC blocking capacitor complicate the circuit and increase size and cost, especially in high-current scenarios.

Innovation Solution

A method that acquires and processes bus voltages during forward and inverse excitations of the transformer to determine bias magnet compensation amounts, adjusting duty cycles without adding capacitors, thereby simplifying the circuit and reducing size and complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a DC blocking capacitor is added to block DC component, then bias magnet is eliminated, but circuit complexity increases and device size increases

Engineering Contradiction:
Improvebias magnet eliminationVSAvoidcircuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the DC blocking function from a separate capacitor component and integrates it into the existing transformer structure through a specific winding connection method. The secondary winding is connected to the primary winding through a tap point, creating an inherent DC blocking path without requiring additional capacitor components. This resolves the contradiction by eliminating bias magnet while maintaining simple circuit topology.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the DC blocking function with the transformer's primary and secondary windings. By connecting the secondary winding terminal to the primary winding through a tap point, the transformer structure itself performs both voltage transformation and DC blocking functions. This integration eliminates the need for separate DC blocking capacitors, reducing circuit complexity and device size while maintaining reliability.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If a DC blocking capacitor is added to block DC component, then bias magnet is eliminated, but device size increases

Engineering Contradiction:
Improvebias magnet eliminationVSAvoidconverter size
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent extracts the DC blocking function from a separate capacitor component and integrates it into the existing transformer structure through a specific winding connection method. The secondary winding is connected to the primary winding through a tap point, creating an inherent DC blocking path without requiring additional capacitor components. This resolves the contradiction by eliminating bias magnet while maintaining simple circuit topology.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the DC blocking function with the transformer's primary and secondary windings. By connecting the secondary winding terminal to the primary winding through a tap point, the transformer structure itself performs both voltage transformation and DC blocking functions. This integration eliminates the need for separate DC blocking capacitors, reducing circuit complexity and device size while maintaining reliability.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If a DC blocking capacitor is added to block DC component, then bias magnet is eliminated, but costs increase

Engineering Contradiction:
Improvebias magnet eliminationVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent extracts the DC blocking function from a separate capacitor component and integrates it into the existing transformer structure through a specific winding connection method. The secondary winding is connected to the primary winding through a tap point, creating an inherent DC blocking path without requiring additional capacitor components. This resolves the contradiction by eliminating bias magnet while maintaining simple circuit topology.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the DC blocking function with the transformer's primary and secondary windings. By connecting the secondary winding terminal to the primary winding through a tap point, the transformer structure itself performs both voltage transformation and DC blocking functions. This integration eliminates the need for separate DC blocking capacitors, reducing circuit complexity and device size while maintaining reliability.

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

Effectively suppresses bias magnet in transformers by accurately compensating for voltage differences, enhancing operational stability and reducing costs and complexity in DC-DC converters.

Implementation Method 1

a transformer in the DC-DC converter

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3734823B1Method and a device for suppressing magnetic bias
Publication Date: 2023.10.18 ZTE CORP
  • EP3734823B1 patent drawingFigure 1~2(a)
  • EP3734823B1 patent drawingFigure 2(b)~3
  • EP3734823B1 patent drawingFigure 4~5

AI summary

Provided are a method and apparatus for suppressing bias magnet. The method includes: acquiring a bus voltage U1 in the case of a forward excitation of a transformer in a DC-DC converter and a bus voltage U2 in the case of an inverse excitation of the transformer in the DC-DC converter; determining a bias magnet compensation amount Δd1 in the case of the forward excitation of the transformer and a bias magnet compensation amount Δd2 in the case of the inverse excitation of the transformer according to the bus voltage U1 in the case of the forward excitation and the bus voltage U2 in the case of the inverse excitation; and adding the bias magnet compensation amount Δd1 in the case of the forward excitation of the transformer and a loop-output duty cycle signal quantity of the DC-DC converter and outputting an adding result to a switch transistor in a forward excitation, and adding the bias magnet compensation amount Δd2 in the case of the inverse excitation of the transformer and the loop-output duty cycle signal quantity of the DC-DC converter and outputting an adding result to a switch transistor in an inverse excitation.