Masterless Stress Sharing in Switch Mode Power Converters

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Solution Overview

Problem

In multi-phase switch mode power converters, existing control methods face challenges in efficiently sharing stress information between controllers, leading to bandwidth limitations and system instability, especially when the master controller fails, which can cause the entire system to fail.

Innovation Solution

A master-less quasi-democratic stress share scheme is introduced, where only the highest and lowest stress slaves share information, allowing for predictable timing and efficient stress balancing through a single-wire bidirectional serial data transmission, enabling any slave to become a master and share stress information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a master-slave configuration is used for stress sharing, then control information can be centralized, but the system fails completely when the master controller fails

Engineering Contradiction:
Improvesystem reliabilityVSAvoidcontroller configuration complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the master controller role from the system architecture, eliminating the single point of failure. Each slave controller becomes independent and capable of autonomous operation, while still participating in stress sharing through peer-to-peer communication. This removes the critical dependency on a master controller while maintaining the stress balancing function.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the operational parameters of slave controllers from passive receivers to active participants in stress sharing. Each slave controller dynamically adjusts its stress contribution based on real-time conditions and communications with other slaves, enabling the system to adapt without a master controller.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If all slaves respond simultaneously to master's output, then stress sharing can be achieved, but bandwidth limitations are imposed due to worst-case scenarios

Engineering Contradiction:
Improvestress sharing effectivenessVSAvoidcontrol bandwidth
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The patent implements periodic stress information exchange between slave controllers instead of continuous simultaneous responses. Each slave transmits its stress information at predetermined intervals, allowing the system to maintain effective stress sharing while significantly reducing communication bandwidth requirements compared to continuous simultaneous control.

Inventive Principle:
Principle #19Periodic action

3Stability of the object's composition

If conservative designs are used for worst-case situations, then system stability is maintained, but severe bandwidth limitations are imposed

Engineering Contradiction:
Improvesystem stabilityVSAvoidcontrol bandwidth utilization
Core Design Contradiction:
Stability of the object's compositionVSProductivity

Solution Approach 1:

The patent transitions from static conservative design to dynamic adaptive control. Slave controllers dynamically adjust their stress contribution based on real-time system conditions and actual communication bandwidth availability, rather than being constrained by worst-case scenario assumptions. This enables optimal bandwidth utilization while maintaining system stability.

Inventive Principle:
Principle #15Dynamics

4Ease of operation

If a single master controller is used, then control information can be centralized, but the whole system fails when the master fails

Engineering Contradiction:
Improvecontrol information managementVSAvoidsystem fault tolerance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent segments the centralized control function into distributed control capabilities across multiple slave controllers. Each slave maintains independent control information and can autonomously participate in stress sharing, eliminating the single point of failure while preserving efficient control information management through peer-to-peer communication protocols.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2443731B1A digital stress share method
Publication Date: 2019.03.20 POWERVATION
  • EP2443731B1 patent drawingFigure 1
  • EP2443731B1 patent drawingFigure 2
  • EP2443731B1 patent drawingFigure 3

AI summary

The Application is directed at arrangements in which switch mode power converters share a common load. More particularly, the application provides a masterless arrangement in which no single converter controls the operation of the other converters. This is achieved by an arrangement in which each converter attempts to share its current measurement with other converters through an arbitration scheme employed on a data line, with the winning converter providing a defacto current measurement, for example a maximum or minimum, to the overall arrangement.