DC Converter Controller Passive Commutation

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Solution Overview

Problem

Existing DC converters suffer from poor electromagnetic compatibility (EMC) characteristics due to 'hard' switching processes that do not consider the charges in switching elements, leading to increased power dissipation and reduced efficiency.

Innovation Solution

A controller that measures currents through inductances and controls half-bridges to enable passive commutation by waiting for current zero crossings to recharge capacitances, reducing 'hard' switching and improving EMC characteristics, while also optimizing switching element activation to minimize power dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If hard switching is used in DC converter, then switching speed is high and control is simple, but electromagnetic compatibility deteriorates and power dissipation increases

Engineering Contradiction:
Improveswitching speedVSAvoidelectromagnetic compatibility
Core Design Contradiction:
SpeedVSObject-affected harmful factors

Solution Approach 1:

The controller performs preliminary measurement of inductance current before switching. Based on the measured current magnitude and direction, the controller determines the optimal switching timing to achieve soft commutation, thereby reducing electromagnetic interference while maintaining efficient power conversion.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously measures the current through each inductance and uses this feedback to control the switching elements. The controller adjusts switching timing based on real-time current measurements, enabling adaptive soft switching that improves electromagnetic compatibility while optimizing power dissipation.

Inventive Principle:
Principle #23Feedback

2Device complexity

If hard switching is used in DC converter, then device complexity is low, but power dissipation increases

Engineering Contradiction:
Improvedevice complexityVSAvoidpower dissipation
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The controller measures the current through each inductance in real-time and uses this feedback to optimize switching timing. This adaptive control reduces power dissipation by avoiding hard switching losses, while the additional measurement and control logic complexity is minimized through efficient implementation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system changes the switching parameter timing based on measured current conditions. By adjusting when switching occurs based on real-time current magnitude and direction, the system minimizes power dissipation during transitions while maintaining overall system efficiency.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If current measurement and adaptive switching control are implemented, then electromagnetic compatibility and power efficiency improve, but device complexity increases

Engineering Contradiction:
Improveelectromagnetic compatibilityVSAvoiddevice complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The controller performs multiple functions using the same measurement and control infrastructure. The current measurement serves both for determining switching timing and for monitoring system state, while the control logic handles both electromagnetic compatibility optimization and power dissipation reduction, reducing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses its own current measurements to automatically optimize its switching behavior. The controller self-adjusts switching timing based on real-time feedback without requiring external intervention or complex additional control systems, enabling the system to improve its own performance characteristics.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2567453B1A controller and a method for a DC converter, and also a DC converter
Publication Date: 2019.11.27 BRUSA ELEKTRONIK AG
  • EP2567453B1 patent drawingFigure 1~3
  • EP2567453B1 patent drawingFigure 2
  • EP2567453B1 patent drawingFigure 4

AI summary

A controller (2) and a method for a DC converter (1 ), wherein the DC converter (1 ) comprises an input (E), an output (A), a connection to ground (GND), and also at least two half-bridges with two switching elements each (TR1..TR4) connected in series and an inductance (LI, L2) each connected with the point connecting the two switching elements. In accordance with the invention the controller (2) is equipped to measure the current (IL1, IL2) through the inductances (LI, L2), and controls the switching elements (TR2, TR4)/(TR1, TR2) positiones on the ground side/input side always with negative/positive current through the inductance (LI, L2) into an off-state. Finally a DC converter (1 ) connected with the controller (2) is also specified.