Cascaded Half-Bridge Solid-State Transformer for Wide Output Range
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Solution Overview
Problem
Existing battery charging systems face challenges in achieving a very wide output range efficiently, which compromises the design of regulation stages and overall system efficiency.
Innovation Solution
A power converter system comprising a solid-state transformer with multiple isolated DC outputs, half bridge converter stages connected in a cascade configuration, and a shared output inductor, controlled using phase shift control to process full output current while handling only a fraction of the output voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a converter is designed to support a very wide output range, then adaptability is improved, but system efficiency deteriorates
Solution Approach 1:
The power converter is divided into multiple half-bridge converter stages, each handling a specific voltage range. This segmentation allows each stage to operate efficiently within its designated range while collectively covering a wide output range, resolving the contradiction between adaptability and efficiency.
2Adaptability or versatility
If auxiliary switches are added to reconfigure the converter for wide output range, then adaptability is improved, but device complexity increases
Solution Approach 1:
Each half-bridge converter stage is designed to perform multiple functions: voltage conversion, power delivery, and regulation. This multi-functionality eliminates the need for auxiliary switches and complex reconfiguration mechanisms, achieving wide output range support without increasing device complexity.
3Adaptability or versatility
If a multi-cell converter is used to multiply output range, then adaptability is improved, but device complexity increases
Solution Approach 1:
Multiple half-bridge converter stages are merged into a unified cascade configuration with a shared output inductor. This merging approach achieves the output range multiplication effect of multi-cell converters while simplifying the overall structure by eliminating redundant components and reducing device complexity.
4Adaptability or versatility
If regulation stages are designed for wide output range, then adaptability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The regulation function is segmented across multiple half-bridge stages, each responsible for a specific voltage range. This segmentation relaxes the manufacturing precision requirements for each individual stage compared to designing a single regulation stage for the entire wide output range, as each stage operates within a narrower, more controlled parameter range.
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 allows for efficient operation across a wide output range, optimizing the utilization of components and achieving high efficiency, while reducing the size and core loss of the magnetic components.
Implementation Method 1
a solid-state transformer having a DC input and a plurality of isolated DC outputs
Implementation Method 2
a half bridge converter stage for each isolated DC output of the solid-state transformer, wherein an input of each half bridge converter stage is connected to the corresponding isolated DC output
Implementation Method 3
an output inductor shared by the half bridge converter stages and configured to deliver an output current
Implementation Method 4
a controller configured to implement phase shift control of the half bridge converter stages relative to one another
Data Source
AI summary
A power converter includes: a solid-state transformer having a DC input and isolated DC outputs; a half bridge converter stage for each isolated DC output of the solid-state transformer, wherein an input of each half bridge converter stage is connected to the corresponding isolated DC output and an output of the half bridge converter stages are electrically connected in a cascade configuration; an output inductor shared by the half bridge converter stages and configured to deliver an output current; and a controller configured to implement phase shift control of the half bridge converter stages relative to one another, based on the number of half bridge converter stages and an output voltage of the power converter being regulated, such that each half bridge converter stage processes the full output current but only a fraction of the output voltage. Methods of controlling the power converter are also described.