Switched Mode Power Supply Phase Synchronization
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Solution Overview
Problem
Switched mode power supply assemblies with multiple units connected in parallel face challenges in minimizing ripple amplitude and preventing subharmonics, particularly when operating independently, and existing solutions with simpler control circuitry are complex and inefficient.
Innovation Solution
A power supply assembly with a common control device that detects phase relationships between units and adjusts switching frequencies to ensure interleaved operation, reducing ripple amplitude and subharmonics by synchronizing the units' output peaks in a ring-configuration, using ramping voltages to maintain phase differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple power supply units are connected in parallel to provide higher output power, then the output power increases and component size can be reduced, but the ripple amplitude of the output current increases when units operate independently
Solution Approach 1:
The patent applies periodic action by implementing interleaved operation where multiple power supply units switch at different phases. Each unit operates with a phase shift relative to others, causing their ripple components to occur at different times. This temporal distribution of switching actions results in ripple cancellation when currents are combined, reducing the overall ripple amplitude while maintaining high output power capability.
Solution Approach 2:
The patent implements dynamics by dynamically adjusting the switching phases of individual power supply units. A control mechanism continuously monitors and adjusts the phase relationships between units to maintain optimal interleaved operation. This dynamic control ensures that units operate in a coordinated manner, adapting to load conditions while minimizing ripple through phase-shifted switching patterns.
2Device complexity
If power supply units operate independently, then the control circuitry is simpler, but subharmonics are caused in the output current
Solution Approach 1:
The patent implements feedback by introducing a control mechanism that monitors the operation of each power supply unit and adjusts their switching phases accordingly. The control system receives feedback signals from each unit and dynamically adjusts the phase relationships to maintain optimal interleaved operation, preventing subharmonic generation while keeping the control architecture relatively simple through standardized feedback loops.
Solution Approach 2:
The patent uses an intermediary control mechanism that coordinates between independently operating power supply units. This intermediary controller manages the phase relationships and synchronization without requiring complex interconnection between units, acting as a mediator that enables coordinated operation while maintaining the simplicity of individual unit designs and avoiding subharmonic issues.
3Object-generated harmful factors
If power supply units operate in synchronization with shifted phases, then the ripple amplitude is reduced, but the control circuitry becomes more complex
Solution Approach 1:
The patent implements periodic action with fixed phase shifts between power supply units, creating a predictable and repeating switching pattern. This periodic interleaved operation reduces ripple amplitude through constructive cancellation of ripple components. The fixed periodic nature of the phase-shifted switching simplifies control circuitry compared to dynamic adjustment methods, as units can operate with predetermined phase relationships.
Solution Approach 2:
The patent applies preliminary action by pre-configuring the phase shifts between power supply units before operation begins. The control system is designed with predetermined timing relationships and phase offsets that are established in advance, eliminating the need for complex real-time calculation and adjustment during operation. This preliminary setup of phase relationships achieves ripple reduction while keeping control circuitry relatively simple.
Data Source
AI summary
A switched mode power supply assembly (1) is described, comprising at least two switched mode power supply units (10i) coupled to each other in parallel; each power supply unit (10i) having an output stage (50i, 60i) capable of selectively operating in a first mode wherein its output signal (IOUT,I) is increasing and operating in a second mode wherein its output signal (IOUT,i) is decreasing; a control device (100) receiving mode switch control signals from all power supply units (10i); wherein the control device (100), if it finds that the actual phase relationship between two power supply units deviates from an optimal phase relationship, is designed to generate synchronising control signals for at least one power supply unit (102), effectively changing the timing of at least one mode switch moment, such that the deviation between the actual phase relationship and said optimal phase relationship is reduced.