Series-Parallel DC/DC Converter Branches for High Voltage
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Solution Overview
Problem
Existing DC/DC conversion systems face challenges in achieving high voltage input, high power output, small size, and low cost, particularly when dealing with high input voltages like 800V, as they require costly high-voltage switching devices and large, costly magnetic components.
Innovation Solution
A DC/DC conversion system comprising multiple switch conversion branches with primary and secondary side circuits connected in series, using a single output filter circuit and reducing transformer size, along with phase-differenced driving signals to minimize component ratings and EMI interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If parallel switching devices or parallel switching converters are used to increase output power, then output power is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges multiple switch conversion branches into a unified series-parallel configuration where primary sides are connected in series and secondary sides are connected in parallel. This combining approach achieves high output power through parallel secondary connections while maintaining lower complexity by sharing a common magnetic component (transformer) and control structure across all branches, rather than using completely separate parallel converters.
Solution Approach 2:
The patent segments the power conversion function into multiple switch conversion branches, each handling a portion of the total power conversion. This segmentation allows the system to achieve high output power by combining multiple smaller conversion units, while each individual branch maintains manageable complexity with standardized circuit topologies and control schemes.
2Loss of energy
If high voltage input (800V) is implemented, then efficiency is improved, but component cost and availability worsen
Solution Approach 1:
The patent segments the high voltage input handling by connecting primary sides of multiple branches in series, effectively distributing the 800V input across several smaller voltage segments. Each switch conversion branch handles a portion of the total voltage, allowing the use of lower-voltage-rated (and thus lower-cost and more readily available) switching devices while maintaining the overall high voltage input capability through the series connection configuration.
Solution Approach 2:
The patent changes the voltage distribution parameters by using series connection of primary sides, which transforms the voltage stress distribution across the system. Instead of requiring single high-voltage components, the system uses multiple lower-voltage components in series, changing the operational parameters of individual components to match available and cost-effective parts while maintaining the required overall voltage level.
3Volume of stationary object
If series connection of primary sides and secondary sides is used, then component size and cost are reduced, but EMI interference increases
Solution Approach 1:
The patent employs periodic switching action with phase-differenced driving signals across multiple switch conversion branches. This periodic switching creates synchronized current waveforms that can cancel out electromagnetic interference through constructive and destructive interference patterns. The phase differences in switching timing ensure that not all branches switch simultaneously, distributing EMI events over time and reducing peak interference levels while maintaining compact component sizes.
4Object-generated harmful factors
If phase-differenced driving signals are used, then EMI interference is reduced, but control complexity increases
Solution Approach 1:
The patent uses periodic switching with fixed phase differences between driving signals of different branches. This periodic action creates predictable, repeating EMI patterns that can be managed through proper timing and synchronization. The phase-differenced signals are generated using regular timing circuits and delay elements, maintaining control complexity at a manageable level while effectively reducing EMI through the periodic cancellation effect.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces the size and cost of components, improves efficiency, and decreases EMI, enabling effective high-voltage input and high-power output while maintaining a compact design.
Implementation Method 1
a transformer, having a primary winding coupled to the primary side circuit; and a secondary side circuit, coupled to a secondary winding of the transformer
Data Source
AI summary
The present disclosure relates to a DC/DC conversion system, including a plurality of switch conversion branches, each of the switch conversion branches includes: a primary side circuit, having an input end connected in parallel with an input capacitor; a transformer, having a primary winding coupled to the primary side circuit; and a secondary side circuit, coupled to a secondary winding of the transformer, wherein, input ends of the primary side circuits of the plurality of switch conversion branches are connected in series to form a system input end, output ends of the secondary side circuits of the plurality of switch conversion branches are connected in series to form a system output end, and a filter circuit is connected in parallel with the system output end.