Zigzag Autotransformer for Delta-Wye Voltage Conversion
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Solution Overview
Problem
Current power distribution systems in facilities like data centers face inefficiencies when converting between 480V delta and 230/400V wye systems due to the need for delta-wye isolation transformers, which result in energy losses and incompatibility with computer power supplies operating at 480V or 277V.
Innovation Solution
A zigzag transformer with an auxiliary winding set on magnetic cores provides a voltage transformation from 277V phase-to-neutral to 230V phase-to-neutral, allowing for efficient power conversion without the need for isolation transformers and supporting unbalanced loads with a stiff voltage supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a delta-wye isolation transformer is used to convert from 480V delta to 230/400V wye, then voltage conversion is achieved, but energy loss increases by approximately 2%
Solution Approach 1:
The patent combines the zigzag transformer and autotransformer into a single integrated device. The zigzag windings create a synthetic neutral while the autotransformer windings provide voltage transformation, merging two previously separate functions into one unified transformer structure. This eliminates the need for separate isolation transformers and reduces energy losses.
Solution Approach 2:
The integrated transformer performs multiple functions simultaneously: it provides voltage transformation (autotransformer function), creates a neutral point (zigzag function), and enables both delta and wye connections. This multi-functionality eliminates the need for separate specialized transformers for each function, reducing overall system energy loss.
2Loss of energy
If computer power supplies are modified to operate at 480V or 277V, then energy efficiency improves, but compatibility with existing power supplies decreases
Solution Approach 1:
The integrated transformer provides adjustable voltage transformation ratios through its autotransformer windings, enabling it to output various voltage levels (230V, 208V, etc.) from a 480V or 277V input. This allows existing 230V-compatible power supplies to be used without modification while maintaining high input voltage operation for efficiency.
3Productivity
If a zigzag transformer with auxiliary winding set is used, then voltage transformation efficiency improves, but device complexity increases
Solution Approach 1:
The patent integrates the zigzag windings and autotransformer windings into a single transformer core structure, sharing common magnetic paths and physical space. This merging reduces the overall device size and complexity compared to having separate zigzag and autotransformer units, while maintaining the efficiency benefits of both configurations.
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 solution reduces energy losses and supports unbalanced loads with minimal phase shift, increasing energy efficiency and reducing transformer size for a given kVA load, while being compatible with existing power supply configurations.
Implementation Method 1
A transformer includes first, second and third magnetic cores. A first winding is on the first magnetic core and has a first terminal configured to provide a first AC phase connection.
Data Source
AI summary
A transformer includes a zigzag transformer comprising first, second and third magnetic cores. The transformer further includes an auxiliary winding set comprising respective pairs of series-connected windings on respective pairs of the first, second and third magnetic cores, the pairs of series-connected windings having respective first terminals connected to respective AC phases of the zigzag autotransformer and respective second terminals configured to provide respective AC output phases.