Master-Slave Power Supply Control for Load Balance
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Solution Overview
Problem
Existing information handling systems face challenges in maintaining load balance and stability among redundant power supplies, leading to oscillatory behavior and 'voltage walking' due to design compatibility issues and limited design margins in active current sharing methods.
Innovation Solution
A power supply system with micro-controllers and switches that dynamically designate each power supply as either a master or slave, controlling the common share bus voltage to prevent oscillations by ensuring only one power supply sets the voltage at a time, thereby maintaining accurate current sharing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active current sharing method with common share bus is used, then power supplies can share load, but oscillatory behavior and voltage walking occur due to design compatibility issues
Solution Approach 1:
The patent segments the power supply system into master and slave power supplies, where only the master power supply connects to the common share bus while slave power supplies remain isolated. This segmentation eliminates the oscillatory interactions between multiple power supplies that occur in traditional parallel configurations, thereby resolving the stability issue without requiring complex compatibility designs.
Solution Approach 2:
The patent introduces a master power supply as an intermediary that mediates between the common share bus and the slave power supplies. The master power supply controls the bus voltage and current distribution, preventing direct interaction between slave power supplies that would cause oscillations. This intermediary approach maintains load sharing functionality while eliminating stability problems.
2Reliability
If master-slave power supply configuration is used, then load sharing can be achieved, but voltage walking occurs due to role changes between master and slave
Solution Approach 1:
The patent establishes the master-slave configuration in advance before the power supplies begin operation. The master power supply is predetermined and remains fixed in that role, preventing any role changes during operation. This preliminary designation eliminates voltage walking by ensuring the master-slave relationship remains stable throughout the system's operation.
Solution Approach 2:
The patent creates an asymmetric master-slave configuration where the master power supply has different functionality (connecting to common share bus, controlling voltage) compared to slave power supplies (isolated, following master's voltage). This asymmetric design prevents role ambiguity and ensures stable current sharing by maintaining fixed functional differences between master and slave units.
3Reliability
If power supplies are designed for full load capability, then safety is ensured, but efficiency and size are compromised
Solution Approach 1:
The patent applies partial action by having only the master power supply designed for full load capability while slave power supplies are designed for partial load operation. The master power supply handles the full range of power demands, while slave power supplies operate at reduced capacity, optimizing their efficiency and size without compromising overall system safety since the master provides the necessary headroom.
Data Source
AI summary
A power supply system comprises a first power supply including a first converter for providing a first output voltage and a first micro-controller coupled to a first switch. The first switch is coupled to a common share bus. A second power supply includes a second converter for providing a second output voltage and a second micro-controller coupled to a second switch. The second switch is also coupled to the common share bus. The first micro-controller is configured to receive a first control signal designating the first power supply to be either a master power supply or a slave power supply and the second micro-controller is configured to receive a second control signal designating the second power supply to be either the master power supply or the slave power supply.