Multi-Port Converter Topology for Ripple Reduction
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Solution Overview
Problem
Existing cascaded buck converter topologies suffer from high frequency switching ripple voltage at input and output terminals, leading to increased component count, size, loss, and cost, while struggling to achieve full output voltage range and charge balancing across all possible output voltages.
Innovation Solution
The multi-port converter topology features a double-input single-output module with a single filter inductor placement across inner switches, allowing for bidirectional energy exchange, power sharing, and reduced component ratings, and can be cascaded with modules of varying topologies to achieve arbitrarily small high frequency switching ripple and full output voltage range capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple two-quadrant buck converter cells with associated filters are connected in series to form classical cascaded buck converters, then the output voltage can be significantly higher than individual input voltages, but the size and number of energy storage components (inductors and capacitors) increase
Solution Approach 1:
The patent merges multiple buck converter cells to share a single common output filter instead of each cell having its own separate filter. This consolidation reduces the total number of energy storage components while maintaining the ability to achieve high output voltages through series connection of the converter cells.
Solution Approach 2:
The common output filter serves all multiple buck converter cells simultaneously, making it a universal component that performs the filtering function for the entire cascaded system rather than requiring dedicated filters for each individual cell.
2Device complexity
If a single L-C low-pass filter is shared among cascaded buck converter cells, then the number of components is reduced, but high frequency switching ripple voltage appears at input and output terminals
Solution Approach 1:
The patent segments the filtering function by placing individual input filters at each buck converter cell input and a single common output filter at the final output. This segmentation allows each input filter to handle ripple at its specific location while the common output filter manages overall output ripple, reducing total ripple voltage throughout the system.
3Object-generated harmful factors
If individual L-C filter elements are sufficiently large to reduce high frequency switching ripple voltage, then ripple is minimized, but the overall increase in both the size and number of energy storage components occurs
Solution Approach 1:
The patent combines multiple filter functions into a single common output filter that serves all buck converter cells. This merging approach reduces the total number of large filter components needed while still achieving effective ripple reduction through the coordinated operation of the common filter and individual input filters.
Data Source
AI summary
A module for interconnecting a pair of DC sources or a pair of DC loads into a DC bus includes: a first port for each source or load; a switching cell for each first port, each cell having a pair of terminals and a switching node; a second port operatively connected to the DC bus and having a pair of terminals, one of the pair of terminals of the second port being connected to one of the terminals of one of the cells and the other of the pair of terminals of the second port being connected to one of the terminals of the other of the cells; and a filter inductor connected between the switching nodes of the cells. Systems including the module and methods utilizing the system are also disclosed.