Twelve-Phase Transformer-Rectifier Harmonic Minimization
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Solution Overview
Problem
Current twelve-phase static rectifier transformers do not effectively improve the quality of electrical networks on aircraft by minimizing first harmonic current frequencies, leading to inefficiencies in power supply and overall power factor.
Innovation Solution
A twelve-phase static electric rectifier transformer configuration featuring a primary circuit with three star-connected primary coils and a secondary circuit with three first and three second secondary coils, where the secondary coils form a hexagonal loop with opposing winding directions, providing a simpler and cost-effective AC-DC conversion solution with equivalent power density to existing aircraft equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional twelve-phase rectifier transformer with separate star and delta secondary circuits is used, then galvanic isolation and voltage transformation are achieved, but the first harmonic current frequencies are not minimized and power factor remains suboptimal
Solution Approach 1:
The patent merges the star and delta secondary circuits into a single hexagonal secondary circuit with six coils. This unified configuration creates a 30° phase shift between opposite coils, which minimizes first harmonic current frequencies and improves power factor while maintaining galvanic isolation and voltage transformation functionality.
2Reliability
If a hexagonal secondary circuit configuration is implemented, then first harmonic frequencies are minimized and power factor improved, but the circuit topology becomes more complex
Solution Approach 1:
The hexagonal secondary circuit serves multiple functions simultaneously: it provides galvanic isolation, transforms voltage, creates the necessary 30° phase shift for harmonic minimization, and delivers power to both rectifier circuits. This multi-functionality reduces the need for separate star and delta circuits, simplifying the overall topology while improving performance.
3Power
If six secondary coils are used to form a hexagonal loop, then equivalent power density and voltage amplitudes are achieved, but manufacturing complexity increases
Solution Approach 1:
The secondary circuit is segmented into six distinct coils arranged in a hexagonal loop, with each coil wound in alternating directions. This segmentation allows for modular manufacturing and assembly while achieving the required power density and voltage characteristics. The alternating winding directions are systematically arranged to create the necessary phase shifts.
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 minimizes or eliminates first harmonic current frequencies, improving the power factor and relieving electrical generators by achieving a 30° phase shift between secondary voltages, meeting aeronautical standards and providing identical voltage amplitudes to both rectifier circuits.
Implementation Method 1
energy is transferred from the primary circuit to the secondary circuit via a magnetic circuit formed by the transformer casing. These two circuits are then magnetically coupled, which provides galvanic isolation between them.
Implementation Method 2
two hexaphasic rectifiers 50 and 60, each formed by a bridge of six diodes 70
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates a twelve-phase static-electric transformer-rectifier (1) comprising a transformer (4) and a first and a second three-phase rectifier circuit (5, 6) intended to be coupled to a load (3), the transformer (4) comprising a primary circuit (10) having three primary windings (12) arranged in a wye configuration and a secondary circuit (11) comprising three first secondary windings (13) and three second secondary windings (14) separate from the first secondary windings (13). The secondary circuit (11) of the transformer (4) comprises a loop of six secondary windings (13 and 14) formed by electrically connecting the three first secondary windings (13) to the three second secondary windings (14) of the secondary circuit (11).