A Center-Tapped Transformer Based Multifunctional Single-Phase Converter with Wide DC-Bus Control

Area of Science:

• Electrical Engineering
• Power Electronics
• Renewable Energy Systems

Background:

• Increasing demand for efficient power converters due to distributed generation and loads.
• Rise of grid-interfaced renewable energy sources (RES), battery energy storage systems (BESS), and DC grids.
• Need for improved controllability and reliability in bidirectional AC-DC converters.

Purpose of the Study:

• To present a center-tapped transformer-based single-stage single-phase full-bridge (FB) bidirectional AC-DC converter.
• To introduce a control strategy for enhanced controllability and reliability.
• To validate the proposed topology for applications like DC distribution, PV/BESS grid interfacing, and vehicle-to-grid (V2G).

Main Methods:

• Introduction of a single-phase center-tapped transformer for galvanic isolation and inherent inductance.
• Implementation of a wide DC-bus voltage control strategy to achieve single-stage power conversion.
• Detailed discussion of the converter's structure, operation, and basic control scheme.
• Cascading multiple converters for multi-level voltage enhancement.

Main Results:

• A single-stage bidirectional AC-DC converter topology is presented, reducing conversion stages.
• The center-tapped transformer provides galvanic isolation and utilizes leakage inductance for current control.
• Simulation and experimental validation confirm the topology's effectiveness for practical applications.
• The proposed converter achieves a single power conversion process with enhanced control.

Conclusions:

• The developed center-tapped transformer-based bidirectional AC-DC converter offers a reliable and efficient solution.
• The single-stage design simplifies power conversion, suitable for various grid-tied applications.
• The topology demonstrates potential for improving power quality and system integration in modern grids.