Shared ZVT Auxiliary Circuit for Multi-Level Boost Converters
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Solution Overview
Problem
Conventional ZVT auxiliary circuits for multi-level boost converters are complex and add significant size, weight, and complexity due to the requirement of multiple auxiliary components, which hinders the miniaturization and efficiency of high-power converters.
Innovation Solution
A simplified ZVT auxiliary circuit for a multi-level power converter is proposed, featuring two solid-state auxiliary switches connected in series across an input voltage and inductor, with a single auxiliary inductor shared between two switching stages, eliminating the need for diodes and reducing overall component count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ZVT auxiliary circuits are used for multi-level boost converters, then soft-switching performance is improved, but device complexity and weight increase significantly
Solution Approach 1:
The patent merges multiple auxiliary circuits into a single shared auxiliary circuit that serves multiple switching stages. Instead of having separate ZVT auxiliary circuits for each switch, the invention uses one common auxiliary circuit with shared components (auxiliary switch, auxiliary diode, auxiliary inductor) that can assist multiple main switches, thereby reducing overall complexity while maintaining soft-switching capability.
Solution Approach 2:
The auxiliary circuit components are designed to perform multiple functions. The single auxiliary inductor serves multiple switching stages, the auxiliary switch can assist different main switches at different times, and the circuit topology allows the same components to provide ZVT for multiple power switches, achieving multi-functionality and reducing total component count.
2Loss of energy
If conventional ZVT auxiliary circuits are used for multi-level boost converters, then switching losses are reduced, but weight increases due to multiple auxiliary components
Solution Approach 1:
Multiple auxiliary components are merged into a shared auxiliary circuit. Instead of having separate auxiliary switches, diodes, and inductors for each main switch, the invention combines these into a single auxiliary circuit that serves multiple switching stages, significantly reducing the total weight of auxiliary components while maintaining the energy loss reduction benefits of soft-switching.
3Productivity
If switching frequency is increased to reduce device size, then power density is improved, but switching losses and heat generation increase in hard-switching converters
Solution Approach 1:
The auxiliary circuit performs preliminary action by pre-charging or pre-discharging the parasitic capacitances of main switches before they are switched. This prepares the switches for zero-voltage or zero-current switching, enabling high-frequency operation without the excessive switching losses that would otherwise occur in hard-switching converters, thus allowing high power density with acceptable efficiency.
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 design allows for high-frequency switching without increasing the converter's size or weight, enhancing power density and reducing cooling requirements, making it suitable for applications where space and weight are limited, such as aerospace.
Implementation Method 1
an auxiliary inductor Laux connected at one end between the first and second solid state auxiliary switches, the other end being arranged to be connected between two switching stages of the multi-level power converter
Data Source
AI summary
A zero voltage transition, ZVT, auxiliary circuit for a multi-level power converter. The ZVT auxiliary circuit includes first and second solid state auxiliary switches connected in series across a series connection of an input voltage and an input inductor, and an auxiliary inductor Laux connected at one end between the first and second solid state auxiliary switches, the other end being arranged to be connected between two switching stages of the multi-level power converter, in use.