Parallel Boost Converter Hot-Plug Control to Prevent Backfeeding

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Solution Overview

Problem

Current backfeeding in non-isolated boost converters can lead to damage and failure, increasing maintenance costs and reducing system reliability, especially when hot-plugging additional converters without proper isolation.

Innovation Solution

Implementing a communication protocol like CANbus for parallel DC/DC boost converters to exchange voltage information, allowing new converters to determine and soft-start at a bus voltage equivalent to existing converters, preventing current backfeeding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If non-isolated boost converters are connected in parallel without isolation, then device complexity is reduced and cost is lowered, but current backfeeding occurs causing damage to semiconductor devices and reducing reliability

Engineering Contradiction:
Improveconverter structureVSAvoidconverter reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The system performs preliminary actions by having each converter communicate its output voltage to others before parallel operation begins. This allows converters to be aware of voltage levels in advance, preventing current backfeeding when hot-plugged converters are added to the system.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention implements feedback through a communication protocol where converters exchange voltage information. Each converter receives voltage data from others and adjusts its operation accordingly, creating a closed-loop system that prevents harmful current flow while maintaining the simple non-isolated architecture.

Inventive Principle:
Principle #23Feedback

2Adaptability or versatility

If hot-plugging is enabled for additional converters, then system adaptability and maintenance are improved, but voltage differentials cause current backfeeding from higher-voltage to lower-voltage converters

Engineering Contradiction:
Improvehot-plug capabilityVSAvoidcurrent backfeeding
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

Before a hot-plugged converter begins operation, it communicates with existing converters to obtain their output voltage levels. This preliminary information exchange allows the new converter to adjust its voltage to match the bus voltage, preventing current backfeeding upon connection.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the voltage parameter of the hot-plugged converter dynamically. The converter adjusts its output voltage based on feedback from the communication protocol to match the bus voltage, thereby eliminating the voltage differential that would otherwise cause harmful current flow.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If output voltages are communicated between converters via communication protocol, then current backfeeding is prevented, but device complexity and communication infrastructure requirements increase

Engineering Contradiction:
Improveprotection from backfeedingVSAvoidcommunication infrastructure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The communication protocol serves multiple functions: it enables voltage information exchange for backfeeding prevention, facilitates hot-plug operation, and allows system coordination. This multi-functionality reduces the need for separate dedicated circuits for each purpose.

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

Solution Approach 2:

The communication protocol acts as an intermediary that enables voltage information exchange between converters without requiring direct electrical connection or additional isolation circuitry. This mediator approach allows voltage coordination while maintaining the simple non-isolated parallel architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4657732A1System and method for intelligent control of parallel non-isolated boost converters
Publication Date: 2025.12.03 VERTIV CORP
  • EP4657732A1 patent drawingFigure 1
  • EP4657732A1 patent drawingFigure 2
  • EP4657732A1 patent drawingFigure 3

AI summary

A system and method for intelligent control of an array of non-isolated direct current-to-direct current (DC/DC) boost converters, as in a power distribution device, provides for hot-plugging of a new boost converter module into an array of boost converter modules previously connected in parallel, each boost converter module associated with an output voltage and communicatively connected via controller action network (CAN) bus or appropriate communications protocol. The new converter module identifies other converter modules by transmitting a signal via the CANbus, to which the other converter modules respond by transmitting their respective output voltages. The new converter module determines the bus voltage across the converter array based on averaging the output voltages and soft-starts by gradually ramping output voltage to match the bus voltage, thereby reducing or eliminating the risk of current backfeed through the converter modules.