Bidirectional Isolated Multi-Level DC-DC Converter Topology
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Solution Overview
Problem
Conventional bidirectional DC-DC converters face issues with high manufacturing costs, large dimensions, and unidirectional power transmission, while also requiring complex control mechanisms and having low efficiency.
Innovation Solution
A bidirectional isolated multi-level DC-DC converter is designed with a transformer having a primary and secondary side, low-voltage and high-voltage switches, diodes, and a bidirectional switch, operating in boost and buck modes with specific duty cycles to minimize dimensions, reduce costs, and enhance efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional multi-level DC-DC converter uses six high-voltage side switches and two diodes at the high voltage side, then power conversion efficiency is improved and electromagnetic interference is reduced, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent removes two diodes from the high voltage side circuit, extracting unnecessary components while maintaining the core functionality. This simplification reduces device complexity and manufacturing cost while preserving the power conversion efficiency benefits through alternative circuit configuration using the remaining switches and components.
Solution Approach 2:
The remaining high-voltage side switches are configured to perform multiple functions, including rectification and voltage regulation, that were previously handled by separate diodes. This multi-functionality approach maintains the required performance while reducing the total component count and circuit complexity.
2Loss of energy
If a conventional multi-level DC-DC converter uses six high-voltage side switches and two diodes at the high voltage side, then power conversion efficiency is improved, but manufacturing cost increases
Solution Approach 1:
By removing two diodes from the high voltage side, the patent directly reduces component count and associated manufacturing costs. The extraction of unnecessary components simplifies the bill of materials and assembly process while maintaining efficiency through optimized switch utilization.
Solution Approach 2:
The patent replaces expensive diode components with switch-based solutions that can be integrated into existing control systems. This substitution approach reduces manufacturing cost by using more economical components while achieving the same functional outcome through control strategy optimization.
3Ease of manufacture
If a bidirectional DC-DC converter is designed with simplified structure and fewer components, then manufacturing cost and dimensions are reduced, but power transmission capability may be limited
Solution Approach 1:
The patent implements dynamic control strategies that allow the simplified converter structure to adapt its operating characteristics based on power transmission requirements. The control system dynamically adjusts switch duty cycles and timing to maintain full bidirectional power transmission capability despite the reduced hardware complexity.
Solution Approach 2:
The patent utilizes parameter changes in the control signals and switching patterns to compensate for the reduced component count. By dynamically adjusting operational parameters such as duty cycle, switching frequency, and phase timing, the simplified converter maintains equivalent power transmission capability to more complex designs.
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
The solution effectively minimizes dimensions, reduces manufacturing costs, and enhances operational efficiency by controlling DC output voltages in both boost and buck modes, addressing the limitations of conventional converters.
Implementation Method 1
a transformer (10) having a primary and a secondary side
Data Source
AI summary
A DC-DC converter is operated in a boost mode by operating a plurality of low-voltage side switches with a first fixed duty cycle (greater than 0.5), with cutting off a plurality of the first high-voltage side switches and a plurality of the second high-voltage side switches, with conducting a plurality of the first diodes of the first high-voltage side switches and a plurality of the second diodes of the second high-voltage side switches, and with alternatively conducting and cutting off a bidirectional switch. In a buck mode, the low-voltage side switches are cut off and a plurality of diodes of the low-voltage side switches are conducted. Furthermore, the first high-voltage side switches are complemented and are operated with a second fixed duty cycle (less than 0.5) while the second high-voltage side switches are conducted and cut off alternatively and the bidirectional switch is switched on and off.