Parallel Boost Converter Hot-Plug Control Against Current Backfeed

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Solution Overview

Problem

Current backfeeding in non-isolated boost converters leads to damage and reduced reliability, necessitating improved management to prevent converter failure and maintenance costs.

Innovation Solution

Implementing a communication protocol like CANbus for parallel DC/DC boost converters to exchange voltage information, allowing new converters to soft-start and adjust their output voltage to match the bus voltage, thereby 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 hot-plugging is enabled, but current backfeeding occurs causing damage to semiconductor devices

Engineering Contradiction:

Improveconverter isolation structureVSAvoidsemiconductor device protection

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The system performs preliminary voltage detection and comparison before allowing current flow between converters. The control circuit detects output voltages of all parallel converters and identifies the highest voltage converter, then prevents backfeeding by controlling switch timing based on this preliminary information, eliminating the need for isolation while protecting semiconductor devices.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by continuously monitoring output voltages of all parallel converters and using this information to control the switching operations. The control circuit receives voltage feedback from each converter and adjusts switching timing to prevent current backfeeding from higher voltage converters to lower voltage converters, maintaining reliability without isolation.

Inventive Principle:

Principle #23Feedback

2Adaptability or versatility

If hot-plugging is enabled for parallel converters, then system adaptability is improved, but voltage differences between converters cause current backfeeding

Engineering Contradiction:

Improvehot-plugging capabilityVSAvoidcurrent backfeeding from voltage differences

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

When a converter is hot-plugged into the parallel system, the control circuit performs preliminary voltage detection to identify the highest output voltage among all converters before allowing the new converter to operate. This preliminary action ensures that the new converter's switching is synchronized with the existing converters, preventing current backfeeding caused by voltage differences and enabling safe hot-plugging.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts switching timing based on real-time voltage conditions. When converters are hot-plugged or removed, the control circuit detects voltage changes and dynamically modifies the switching operations of all parallel converters to maintain proper voltage relationships, preventing backfeeding while maintaining adaptability.

Inventive Principle:

Principle #15Dynamics

3Reliability

If isolation is added to prevent current backfeeding, then reliability is improved, but device complexity and maintenance costs increase

Engineering Contradiction:

Improveconverter protection from backfeedingVSAvoidisolation circuitry

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts and removes the isolation components from the converter design while maintaining protection against current backfeeding. By using control circuitry to detect voltages and manage switching timing, the system achieves backfeeding protection without the physical isolation barriers, thereby reducing device complexity and maintenance requirements while preserving reliability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The system replaces mechanical/isolation-based protection with an electronic control-based protection mechanism. Instead of using isolation circuitry to physically prevent backfeeding, the control circuit uses voltage detection and switching timing control to electronically prevent harmful current flow, reducing complexity while maintaining reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS20250373172A1System and method for intelligent control of parallel non- isolated boost converters

Publication Date: 2025.12.04 VERTIV CORP

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.