Bidirectional DC-DC Converter with Inductor Segmentation
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Solution Overview
Problem
Existing high voltage-gain bidirectional DC-DC converters face issues with low efficiency, high switch voltage stress, and complex control systems, particularly at high-line light-load conditions, due to narrow ZVS range and high conduction losses, which affect the stability and reliability of energy transfer in renewable energy storage systems.
Innovation Solution
A bidirectional DC-DC converter design incorporating first and second inductors, high and low side switch modules, clamping capacitors, and a switching control circuit that operates in multiple modes to demagnetize and magnetize inductors, reducing voltage stress on switches and achieving higher voltage gain with reduced component losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If isolated converters (DAB, resonant) are used to achieve high voltage gain, then voltage gain is improved, but efficiency deteriorates due to narrow ZVS range, high conduction losses, and complicated control systems
Solution Approach 1:
The converter is divided into two independent inductors (L1 and L2) instead of using a single transformer, allowing independent control of magnetizing and leakage inductance functions. This segmentation enables broader ZVS range and reduced conduction losses while maintaining high voltage gain capability.
Solution Approach 2:
Instead of using a transformer to achieve isolation and voltage gain, the patent inverts the approach by using two independent inductors with a clamping capacitor to achieve the same functions. This non-isolated topology eliminates transformer losses while maintaining voltage gain through inductor-based energy storage and transfer.
2Device complexity
If non-isolated buck-boost converter is used for high voltage applications, then simplicity is improved, but output regulation accuracy deteriorates due to duty ratio limitation
Solution Approach 1:
The patent introduces a new dimension to the buck-boost topology by adding a clamping capacitor connected to two independent inductors. This dimensional expansion allows the converter to achieve high voltage gain with extended duty ratio range, improving output regulation accuracy while maintaining operational simplicity.
Solution Approach 2:
The converter employs dynamic switching control of four switches (S1, S2, S3, S4) with complementary conduction patterns. This dynamic operation allows continuous adjustment of the effective duty ratio beyond traditional limits, enabling accurate output voltage regulation across a wide input voltage range.
3Force
If high voltage stress components are used to achieve high voltage gain, then voltage gain is improved, but component losses and cost increase
Solution Approach 1:
The patent changes the voltage stress parameters by distributing the voltage across two inductors and a clamping capacitor rather than concentrating it on single high-stress components. This parameter distribution allows using standard-voltage-rated components to achieve high overall voltage gain, reducing component losses and cost.
Solution Approach 2:
The clamping capacitor acts as an intermediary energy storage element between the two inductors, enabling voltage multiplication without requiring high-voltage-rated switches or components. This intermediary component allows standard components to be used while achieving high voltage gain through capacitive energy transfer.
4Power
If interleaved inductors are used in high frequency operation, then power density is improved, but current balancing becomes difficult
Solution Approach 1:
The converter uses two separate, independent inductors instead of interleaved inductors, eliminating current balancing issues. Each inductor can be independently designed and controlled, simplifying the operation while maintaining high power density through parallel energy storage and transfer paths.
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 proposed converter achieves higher voltage gain with reduced switch voltage stress and lower component losses, enhancing efficiency and stability, allowing for reliable energy transfer in renewable energy storage systems.
Implementation Method 1
The first inductor is connected between the first input-output terminal and the second input-output terminal... the first inductor is demagnetized and the second inductor is magnetized
Data Source
AI summary
A bidirectional converter with high voltage gain and low switch voltage stress is provided. The bidirectional converter has a first input-output terminal and a second input-output terminal, and includes first and second inductors, first and second high side switch modules, first and second low side switch modules, a first clamping capacitor, first and second capacitors, and a switching control circuit. The switching control circuit is configured to switch between three switching modes.