Resonant Bidirectional Converter for Wide Voltage Range Switching
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Solution Overview
Problem
Conventional bidirectional converters fail to meet the increasing demands of wide input and output voltage ranges required by evolving battery charging systems, particularly in both forward and backward modes.
Innovation Solution
A bidirectional converter design utilizing a transformer with two secondary inductors, a full bridge inverter, and a three-leg rectifier, allowing for selective coupling of secondary inductors based on operating mode to achieve high efficiency across varying voltage ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional bidirectional converter is used, then the structure is simple, but the input and output voltage range is limited
Solution Approach 1:
The converter is segmented into multiple operating modes (first operating mode and second operating mode) with different secondary inductors disconnected in each mode. This segmentation allows the converter to handle different voltage ranges effectively, expanding the overall voltage range capability while maintaining manageable structural complexity through mode-based operation.
Solution Approach 2:
The converter dynamically switches between different operating modes depending on the voltage conditions. The controller selectively disconnects different secondary inductors based on the operating mode, enabling the converter to adapt to varying input and output voltage ranges. This dynamic switching capability resolves the contradiction by making the converter structure flexible rather than fixed.
2Adaptability or versatility
If multiple secondary inductors are used to expand voltage range, then the voltage range increases, but the device complexity increases
Solution Approach 1:
Multiple secondary inductors are designed to serve different functions in different operating modes. The first secondary inductor is disconnected in the first operating mode while the second secondary inductor is disconnected in the second operating mode. This multi-functionality allows each inductor to contribute to different voltage range requirements, expanding the overall voltage range without proportionally increasing complexity.
Solution Approach 2:
The converter changes its electrical parameters (which secondary inductor is connected) based on the operating mode. By selectively disconnecting different secondary inductors through the controller, the converter adjusts its effective turns ratio and voltage transformation characteristics. This parameter changing approach allows the converter to achieve wide voltage range coverage while managing complexity through controlled parameter variation rather than permanent structural complexity.
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 converter operates efficiently in both forward and backward modes, supporting battery charging and power supply functions with increased input and output voltage ranges, enhancing versatility and performance.
Implementation Method 1
The converter includes a resonant tank on the primary side of the transformer
Implementation Method 2
a transformer having a primary inductor coupled to two secondary inductors
Data Source
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AI summary
A bidirectional DC-DC converter having at least two secondary inductors on a secondary side of a transformer. The converter includes at least two switches respectively coupled to the at least two secondary inductors. Through selective operation of the switches, a gain of the converter can be changed by selectively coupling one secondary inductor to a primary inductor in accordance with an operating mode.