Non-symmetrical AC-to-DC Converter with Phase-Shifted Windings
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Solution Overview
Problem
Existing AC-to-DC converters in aerospace/military applications lack efficient voltage boosting capabilities while introducing minimal harmonic distortions, and are often bulky and heavy due to their design, particularly in 12-pulse or 18-pulse configurations.
Innovation Solution
A non-symmetrical AC-to-DC converter design featuring a main rectifier and auxiliary rectifiers with phase-shifted transformer windings, allowing for inductive power transfer and series combination to achieve voltage boosting with reduced low-frequency harmonic distortion, resulting in a more compact and lightweight solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a 24-pulse converter configuration is used to reduce harmonic distortions, then harmonic distortion levels are reduced, but the converter becomes heavier and larger due to increased transformer windings
Solution Approach 1:
The converter is segmented into multiple parallel paths with different pulse configurations (12-pulse and 24-pulse sections). This allows the system to achieve reduced harmonic distortion through the 24-pulse path while the overall weight is managed by optimizing each segment independently rather than requiring a full 24-pulse configuration across the entire system.
Solution Approach 2:
Different parts of the converter are assigned different pulse configurations based on their specific functional requirements. The 12-pulse section handles applications where moderate harmonic reduction is sufficient, while the 24-pulse section provides enhanced harmonic filtering where needed. This local differentiation optimizes the weight-performance ratio.
2Object-generated harmful factors
If a 24-pulse converter configuration is used to reduce harmonic distortions, then harmonic distortion levels are reduced, but the converter becomes larger due to increased transformer windings
Solution Approach 1:
The converter structure is divided into modular segments with different pulse configurations. This segmentation allows for compact arrangement of transformer windings and rectifier bridges, reducing the overall footprint while maintaining the harmonic reduction benefits of 24-pulse operation in critical sections.
Solution Approach 2:
The patent utilizes multi-dimensional spatial arrangement of transformer windings and rectifier components. By optimizing the three-dimensional layout and using overlapping configurations, the converter achieves reduced harmonic distortion without proportionally increasing the planar area occupied by the device.
3Adaptability or versatility
If voltage boosting capability is added to achieve higher output voltages (540V DC, +/-270Vdc, 610V DC), then the converter becomes more versatile, but the device complexity increases
Solution Approach 1:
The converter design incorporates universal transformer windings and rectifier configurations that can operate in multiple modes (12-pulse, 18-pulse, 24-pulse) and provide various output voltage levels (270V DC, 540V DC, +/-270Vdc, 610V DC) without requiring separate dedicated circuits for each function. This multi-functionality is achieved through selective switching and configurable connections.
Solution Approach 2:
The converter employs dynamic switching mechanisms that allow real-time reconfiguration of transformer windings and rectifier bridges. This enables the system to adapt its pulse configuration and output voltage level based on load requirements, maintaining optimal performance across different operating conditions without permanent structural changes.
4Weight of stationary object
If a 12-pulse or 18-pulse converter is used instead of 24-pulse, then the converter is lighter and smaller, but harmonic distortion levels increase
Solution Approach 1:
The converter is divided into functional segments where the 12-pulse or 18-pulse sections provide the primary power conversion with reduced weight, while a dedicated 24-pulse segment or harmonic filtering section addresses the harmonic distortion issue. This segmentation allows the system to achieve acceptable harmonic levels without requiring the full weight penalty of a complete 24-pulse configuration.
Solution Approach 2:
Harmonic filtering circuits or reactive compensation elements are introduced as intermediary components between the 12/18-pulse converter and the power system. These intermediaries actively reduce harmonic distortion levels without requiring the converter itself to be reconfigured into a heavier 24-pulse design.
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 solution achieves a significant reduction in size and weight by improving the W/VA ratio, enabling efficient voltage boosting with minimal harmonic distortion, translating to a 43.6% weight reduction in some configurations.
Implementation Method 1
inductively transferring a second portion of AC power from the primary windings to a first set of secondary windings of the transformer while introducing a phase shift
Implementation Method 2
inductively transferring a third portion of AC power from the primary windings to a second set of secondary windings of the transformer while introducing a phase shift
Data Source
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AI summary
A boosting AC-to-DC converter An AC-to-DC converter may include a main rectifier, a first auxiliary rectifier, a second auxiliary rectifiers and a transformer assembly. The transformer assembly may include a set of primary windings arranged in a first multiphase configuration and connected to the main rectifier, a first set of secondary windings arranged in a second multiphase relationship and connected to the first auxiliary rectifier and a second set of secondary windings arranged in a third multiphase configuration and connected to the second auxiliary rectifier. The second multiphase configuration of the first set of secondary windings and the third multiphase configuration of the second set of secondary windings may be in phase shifting relationships relative to the first multiphase configuration of the set of primary windings.