Three-Wire DC-DC Converter Layout for Return Current Balancing

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Solution Overview

Problem

Existing DC-DC power systems using four-wire converters face issues with uncontrolled return currents, leading to overcurrents that can damage converters due to unequal current distribution.

Innovation Solution

A three-wire DC-DC converter system with a common wiring busbar and controller for equalizing output currents across converters, ensuring consistent current flow through each converter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If four-wire DC-DC converters are used in parallel power supply system, then voltage conversion function is provided, but return current cannot be controlled evenly distributing, causing overcurrent and converter damage

Engineering Contradiction:
Improveconverter reliabilityVSAvoidcurrent distribution control
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent extracts the second power terminal connection from the DC-DC converter by introducing a common wiring busbar. The common wiring terminal connects to the common wiring busbar, which in turn connects to the second power terminal of the direct current load. This separation removes the return current path from the converter's internal circuitry, eliminating the overcurrent problem while maintaining voltage conversion functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The common wiring busbar serves as an intermediary component between the DC-DC converters and the direct current load's second power terminal. By introducing this intermediate connection point, the patent enables multiple converters to share the return current path evenly, preventing any single converter from bearing excessive current stress.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If four-wire DC-DC converters are used, then voltage conversion is achieved, but wiring complexity and system cost increase

Engineering Contradiction:
Improvevoltage conversion capabilityVSAvoidwiring complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent merges the second power terminal connections of multiple DC-DC converters by connecting them all to a common wiring busbar. This consolidation reduces the number of separate connections required, simplifying the wiring structure and reducing system complexity while preserving the voltage conversion capability of each converter.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The common wiring busbar serves multiple functions: it acts as a common return path for all DC-DC converters, provides a centralized connection point for the second power terminal of the load, and enables even current distribution across all converters. This multi-functionality reduces overall system complexity.

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

Data Source

PatentEP4184776B1Three-wire DC-to-DC converter and parallel power supply system
Publication Date: 2025.08.06 HUAWEI DIGITAL POWER TECH CO LTD
  • EP4184776B1 patent drawingFigure 1
  • EP4184776B1 patent drawingFigure 2
  • EP4184776B1 patent drawingFigure 3

AI summary

This application discloses a three-wire DC-DC converter and a parallel power supply system. The parallel power supply system includes a common wiring busbar, an input wiring busbar, an output wiring busbar, and at least two three-wire DC-DC converters. Each three-wire DC-DC converter includes a DC-DC conversion circuit, an input wiring terminal, an output wiring terminal, and a common wiring terminal. Input wiring terminals of all the three-wire DC-DC converters are connected in parallel to the input wiring busbar, output wiring terminals of all the three-wire DC-DC converters are connected in parallel to the output wiring busbar, and the common wiring terminals of all the three-wire DC-DC converters are connected in parallel to the common wiring busbar. The wiring busbar is configured to connect a first direct current power supply and a load. All the three-wire DC-DC converters convert a voltage of the first direct current power supply into a voltage required by the load and output the voltage, and output currents at the output wiring terminals of all the three-wire DC-DC converters are consistent. This avoids a case in which a DC-DC converter is damaged due to an excessively large return current of the DC-DC converter.