Distributed Phase-Shifting Transformer Layout for Modular HVDC Rectification
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Solution Overview
Problem
Centralized phase-shifting transformers in HVDC power supply systems suffer from insufficient safety redundancy, complex winding processes, high cost, and limited scalability, leading to potential system failures and high maintenance costs.
Innovation Solution
A distributed phase-shifting transformer apparatus comprising multiple three-winding transformers with predefined phase angles, allowing for modular expansion and redundancy, reducing harmonic distortion, and enhancing power factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a centralized phase-shifting transformer is used, then the system structure is simple, but the safety redundancy is insufficient and the system capacity cannot be easily increased
Solution Approach 1:
The centralized phase-shifting transformer is divided into multiple distributed three-winding transformers. Each transformer has a primary winding and two secondary windings with a phase angle difference of 30 degrees between them. This segmentation provides safety redundancy as individual transformers can fail independently without causing complete system failure, while maintaining relatively simple individual unit structures.
2Adaptability or versatility
If a centralized phase-shifting transformer with multiple windings is used, then the phase-shifting function is achieved, but the winding process is complex and the cost is high
Solution Approach 1:
The complex multi-winding centralized transformer is segmented into multiple simpler three-winding transformers. Each unit has only one primary winding and two secondary windings, significantly simplifying the winding process and reducing manufacturing complexity while maintaining the overall phase-shifting capability through the distributed configuration.
Solution Approach 2:
Each three-winding transformer is designed with specific local characteristics: the two secondary windings have a fixed 30-degree phase angle difference between them. This local quality approach allows each unit to be manufactured independently with standardized processes, reducing overall system complexity and cost.
3Device complexity
If a centralized phase-shifting transformer is used, then the initial system setup is straightforward, but the scalability is limited and expansion is difficult
Solution Approach 1:
The system transitions from a static centralized transformer configuration to a dynamic distributed architecture where individual three-winding transformer units can be independently added or removed. This enables flexible scalability as system power requirements change, while the initial setup remains straightforward by deploying basic units in parallel.
4Volume of stationary object
If a centralized phase-shifting transformer is used, then the system is compact, but the maintenance cost is high when faults occur
Solution Approach 1:
The system is divided into independent three-winding transformer units that can operate in parallel. When a fault occurs in one unit, only that specific unit needs maintenance while others continue operating, significantly reducing maintenance costs and downtime compared to a centralized transformer where any fault requires complete system shutdown and repair.
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 effectively reduces current harmonics, improves power factor, simplifies production, and lowers maintenance costs by enabling modular expansion and high safety redundancy.
Implementation Method 1
each three-phase three-winding transformer includes first windings on the primary side and second windings and third windings on the secondary side
Implementation Method 2
four rectifier circuits, and positive and negative DC output terminals of the four rectifier circuits
Data Source
AI summary
The present disclosure provides a distributed phase-shifting transforming apparatus, including N transformer rectifier units, where each transformer rectifier unit includes two three-phase three-winding transformers and four rectifier circuits, each three-phase three-winding transformer includes first windings on the primary side and second windings and third windings on the secondary side, AC power output by the second windings and the third windings on the secondary side is output after being rectified by the rectifier circuits. Each transformer rectifier unit is configured such that: one set of the two first windings on the primary side and the two second windings on the secondary side is phase-shifted by 15° from each other, and the other set has the same phase angle; and the second windings and the third windings of each three-phase three-winding transformer are phase-shifted by 30° from each other.