24-Pulse AC/DC Converter with Hexagonal Secondary Windings
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Solution Overview
Problem
Existing AC/DC converters for avionics applications face challenges in achieving high-power quality with low harmonic distortion and size, weight, and cost efficiency, particularly in low-voltage/high-current applications, where Delta-Hex topologies have not provided sufficient power quality for aerospace use.
Innovation Solution
A power converter design featuring a transformer with three primary windings in a delta configuration and three secondary windings split into two portions, forming a closed regular hexagon, with taps distributed at regular angles, and rectification paths having different inductances to achieve 24-pulse direct-current voltage without inter-phase transformers or input inductors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional AC/DC converter topologies are used, then device complexity is reduced, but power quality and harmonic distortion performance deteriorate
Solution Approach 1:
The secondary windings are segmented into multiple portions with taps distributed at regular angles, creating multiple rectification paths (24-pulse configuration) from a single transformer. This segmentation achieves high power quality and low harmonic distortion without requiring multiple separate converters or complex inter-phase transformers.
Solution Approach 2:
The patent employs asymmetric winding configurations where secondary windings are split into portions with different tap positions and configurations. This asymmetry in the winding structure enables the generation of multiple phase-shifted rectification paths, achieving 24-pulse operation and superior harmonic performance.
2Reliability
If high-power quality with low harmonic distortion is achieved, then power conversion performance is improved, but size and weight increase
Solution Approach 1:
The patent merges multiple rectification paths into a single integrated transformer structure with split secondary windings. By combining the functions of multiple transformers or complex filter circuits into one unified device with cleverly configured windings and taps, high power quality is achieved without proportionally increasing weight.
Solution Approach 2:
The transformer structure performs multiple functions simultaneously: voltage transformation, phase shifting, and harmonic filtering. The same windings and core that provide voltage conversion also generate the 24-pulse rectification and reduce harmonics, eliminating the need for separate heavy filtering components.
3Reliability
If high-power quality with low harmonic distortion is achieved, then power conversion performance is improved, but cost increases
Solution Approach 1:
The secondary windings are segmented into multiple portions with taps distributed at regular angles, creating multiple rectification paths (24-pulse configuration) from a single transformer. This segmentation achieves high power quality and low harmonic distortion without requiring multiple separate converters or complex inter-phase transformers.
Solution Approach 2:
The transformer structure itself provides the harmonic filtering and phase-shifting functions through its internal winding configuration and tap arrangements. The windings serve their primary voltage transformation function while simultaneously generating the 24-pulse rectification pattern, making the system self-sufficient and eliminating the need for additional expensive filtering components.
4Weight of stationary object
If transformer size is reduced, then weight and volume are minimized, but power conversion capability deteriorates
Solution Approach 1:
The patent employs a planar or compact winding structure that efficiently utilizes space. The split secondary windings with distributed taps are arranged to maximize magnetic coupling and minimize leakage inductance, achieving high power density in a compact form factor suitable for avionics applications.
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 reduces harmonic distortion to acceptable levels for avionics applications, improves power efficiency, and minimizes size and weight while maintaining high power quality, outperforming traditional topologies by achieving lower AC current distortions and EMI emissions.
Implementation Method 1
a transformer having: three primary windings configured to receive respective phases of a three-phase alternating current (AC) input signal
Implementation Method 2
first means for rectifying multi-phase AC power signals; second means for rectifying multiphase AC power signals
Data Source
Figure 1
Figure 1A
Figure 2
AI summary
A power converter has a transformer having three primary windings configured to receive respective phases of a three-phase alternating current (AC) input signal in a delta configuration and three secondary windings, each split into two portions, wherein the portions are coupled together in a regular hexagon. The power converter includes a rectifier having a first rectifier path coupled between taps of the secondary windings and a positive output of the power converter and a second rectifier path coupled between taps of the secondary windings and a negative output. One of the secondary windings may be reversed with respect to the other secondary windings. The primary windings may be split with a corresponding secondary winding sandwiched between portions of the primary. One of the paths may have a different inductance than the other path.