Modular Multi-Stage DC Converter with Scott Transformer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing devices for converting high DC voltages into lower DC voltages and vice versa, such as those using modular multi-stage power converters, face inefficiencies in current-carrying capacity utilization and high procurement costs due to the need for multiple sub-modules with different capacities.
Innovation Solution
The solution involves a modular multi-stage power converter system that includes a three-phase to single-phase transformer, formed from multiple single-phase-to-single-phase transformers connected in a Scott or LeBlanc circuit, allowing for improved voltage transformation with a smaller number of submodules by using a series connection of multi-stage converters and additional transformers for enhanced transformation ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If modular multi-stage power converters with multiple sub-modules are used to convert high DC voltages, then the voltage transformation capability is improved, but the current-carrying capacity utilization becomes insufficient and procurement costs increase
Solution Approach 1:
The device is divided into multiple multi-stage converters, each handling a portion of the total power conversion task. This segmentation allows each converter to operate at optimal current-carrying capacity while collectively achieving the required high voltage transformation, thus improving utilization efficiency and reducing the total number of sub-modules needed.
Solution Approach 2:
AC voltage is introduced as an intermediary medium between the high DC voltage and lower DC voltage. The multi-stage converters transform DC to AC and back to DC in intermediate steps, enabling more efficient current utilization and reducing the need for excessive sub-modules while maintaining transformation capability.
2Productivity
If two types of sub-modules with different current carrying capacities are used, then the current-carrying capacity utilization is improved, but the procurement costs and operational expenses increase due to different spare parts and large number of sub-modules
Solution Approach 1:
The invention uses sub-modules with uniform current-carrying capacities across all multi-stage converters. This homogenization simplifies procurement, maintenance, and spare parts management while achieving optimal current utilization through the distributed architecture of multiple converters working in parallel.
3Power
If a large number of sub-modules are used to achieve high transformation ratio, then the voltage conversion capability is improved, but the device complexity and cost increase
Solution Approach 1:
The high transformation ratio is achieved by segmenting the conversion process into multiple stages, where each multi-stage converter handles a portion of the total transformation. This approach achieves the required transformation ratio without requiring an excessive number of sub-modules in a single converter, thus reducing overall device complexity.
Solution Approach 2:
The system transitions from a single-dimensional DC-DC conversion to a multi-dimensional DC-AC-DC conversion pathway. By introducing AC voltage as an intermediate dimension and using multiple converters in parallel, the system achieves high transformation ratios more efficiently with fewer sub-modules per converter.
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 enhances the utilization of current-carrying capacity and reduces costs by allowing for efficient conversion of high DC voltages with fewer submodules, achieving a high transformation ratio and cost-effectiveness.
Implementation Method 1
a first transformer (three-phase to single-phase transformer), which has a first winding and a second winding and which transforms the three-phase first AC voltage applied to the first winding into a single-phase second AC voltage applied to the second winding
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a device (2), which transforms a first direct current voltage into a considerably smaller second direct current voltage, or vice versa, with a total power converter (GMMC), which has a first and a second modular multi-stage power converter (11, 12), which are connected in series, wherein the first direct current voltage is applied to the first multi-stage power converter (11) and the second direct current voltage is applied to the series circuit for the multi-stage power converters (11, 12). In order to achieve the transformation at a large voltage difference with a low number of sub-modules, according to the invention: the first multi-stage power converter (11) converts the first direct current voltage into a three-phase first alternating voltage; a first transformer (T1) which has a first winding (W1) and a second winding (W2) transforms the three-phase first alternating voltage applied across the first winding (W1) into a single-phase second alternating voltage applied across the second winding (W2); and the first multi-stage power converter (11) is connected to the first alternating voltage, and the second multi-stage power converter (12) is connected to the second alternating voltage.