Interleaved Converter Master-Slave Synchronization for Ripple Reduction
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Solution Overview
Problem
Traditional switch-mode power supplies (SMPS) with PFC pre-regulators face challenges in achieving high power factor and low total harmonic distortion, especially at higher power levels, due to high input current ripple and filtering requirements, which limit their practical application.
Innovation Solution
The use of a control device for interleaved converters, where one converter is designated as the master and the others as slaves, with a time delay synchronization mechanism to ensure all converters operate at the same frequency, minimizing input current ripple and filtering needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional SMPS with PFC pre-regulators are used, then power factor is improved and total harmonic distortion is reduced, but input current ripple increases and filtering requirements become more stringent
Solution Approach 1:
The patent divides the single PFC converter into multiple interleaved converters operating in parallel. Each converter processes a portion of the input current, and their combined output current ripples are phase-shifted and superimposed to cancel each other out, significantly reducing the total input current ripple while maintaining high power factor correction performance
Solution Approach 2:
The patent implements periodic phase-shifting of the switching cycles among the interleaved converters. By introducing controlled time delays between the switching cycles of different converters, the input current ripples from each converter occur at different phases and cancel each other through constructive interference, achieving ripple reduction without compromising power factor
2Object-generated harmful factors
If multiple interleaved converters are used, then input current ripple is reduced, but device complexity increases due to synchronization requirements
Solution Approach 1:
The patent implements a self-synchronization mechanism where each converter automatically adjusts its switching frequency and phase based on the operation of other converters in the interleaved system. The converters detect and adapt to the switching cycles of their peers, automatically establishing the appropriate phase relationships without requiring external synchronization signals or complex control circuitry
Solution Approach 2:
The patent employs feedback mechanisms where each converter monitors the switching states and current waveforms of other converters and adjusts its own operation accordingly. This closed-loop control ensures that the converters maintain proper phase relationships and synchronization, achieving coordinated operation while keeping the control complexity manageable through decentralized decision-making
3Ease of manufacture
If TM operation mode is used, then ease of manufacture is improved, but power factor correction performance deteriorates at higher power levels due to increased current ripple
Solution Approach 1:
The patent segments the PFC function across multiple TM-operated converters working in parallel. While each individual converter operates in transition mode with inherent current ripple, the combined effect of multiple phase-shifted converters results in significant ripple cancellation, enabling TM operation to maintain high power factor correction performance at higher power levels that would be unachievable with a single converter
Solution Approach 2:
The patent merges the outputs of multiple TM-operated converters to achieve a combined power factor correction performance that exceeds what a single converter could provide. By combining the phase-shifted current waveforms from multiple converters, the system achieves both the manufacturing simplicity of TM operation and the high-performance power factor correction required at higher power levels
Data Source
AI summary
Control device for a switching converter structure comprising at least a first and a second interleaved converter, wherein the control device is configured to designate one converter as master and at least the other converter as slave, to set a time delay of the operating cycle of the slave converter and to synchronize the master and the at the least one slave converter.