Reconfigurable Transformer Ratios for Wide-Range Power Conversion
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Solution Overview
Problem
Conventional power electronic converters face limitations in miniaturization due to the dominance of passive components, particularly transformers, which incur significant copper and core losses, especially in applications requiring high step-up/down ratios and wide operating voltage ranges.
Innovation Solution
The development of a hybrid electronic and magnetic structure, known as the Variable-Inverter-Rectifier-Transformer (VIRT), which enables fractional and reconfigurable effective turns ratios by integrating rectifiers and inverters into the transformer windings, allowing for reduced conduction loss and dynamic adjustment of transformation ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a transformer with large turns ratio is employed to achieve high voltage conversion ratio, then voltage conversion capability is improved, but transformer volume and copper loss increase
Solution Approach 1:
The patent divides the transformer into multiple independent modules, each with a smaller turns ratio. By cascading these modules, the overall high voltage conversion ratio is achieved without requiring a single large transformer, thus reducing the volume of each individual transformer module while maintaining the required voltage transformation capability.
Solution Approach 2:
The patent employs adjustable switching networks that can dynamically reconfigure the transformer connections to provide different effective turns ratios. This dynamic reconfiguration allows the system to achieve high voltage conversion ratios when needed while operating with smaller, more efficient transformer ratios during normal operation, thereby reducing overall copper loss and volume.
2Power
If a high number of turns is placed on the core to achieve large turns ratio, then voltage conversion ratio is improved, but manufacturing complexity and PCB fabrication requirements worsen
Solution Approach 1:
The patent segments the high turns ratio requirement into multiple smaller ratio modules. Each module can be manufactured with a reasonable number of turns that meet standard PCB fabrication capabilities, avoiding the need for extremely fine trace widths and tight spacing that would be required for a single high-ratio transformer.
Solution Approach 2:
The patent introduces dynamically reconfigurable switching networks that can change the effective turns ratio through switching arrangements rather than requiring a fixed high number of physical turns. This dynamic approach achieves high voltage conversion ratios through control strategies rather than through manufacturing increasingly complex high-turn windings.
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 approach reduces turns count and copper loss within the transformer, facilitating miniaturization and efficient operation across wide voltage ranges, particularly beneficial for applications like USB wall chargers and other power electronics.
Implementation Method 1
transformer having a magnetic core and a set of fractional turns
Data Source
AI summary
Described is a hybrid electronic and magnetic structure that enables a transformer with fractional and reconfigurable effective turns ratios (e.g. 12:0.5, 12:2/3, 12:1, and 12:2) and hereinafter referred to as a Variable-Inverter-Rectifier-Transformer (VIRT). A VIRT is valuable in converters having wide operating voltage ranges and high step-up/down, as it offers a means to reduce turns count and copper loss within a transformer while facilitating voltage doubling and quadrupling. Such characteristics are beneficial for reducing the size of a transformer stage in many power electronics applications, such as USB wall chargers. In embodiments, a VIRT comprises a plurality of switching cells distributed around a magnetic core and coupled to half-turns wound through that core. By controlling operating modes of the switching cells, it is possible to gain control over flux paths and current paths in the transformer.