Dual-output hybrid converter based on the modular universal dc-ac/dc converter

Area of Science:

• Electrical Engineering
• Power Electronics
• Renewable Energy Systems

Background:

• Modern electrical power systems increasingly integrate renewable energy sources, driving the need for advanced microgrids.
• Distributed hybrid microgrids offer enhanced reliability and flexibility through islanded operation and coexistence of AC and DC buses.
• Existing power electronic converters require greater standardization and modularity for efficient microgrid integration.

Purpose of the Study:

• To advance the modular universal converter (MUC) concept by developing a single-stage, dual-output hybrid converter.
• To enable simultaneous supply of a three-phase four-wire AC port and a regulated DC bus.
• To replace conventional dual-output configurations relying on separate DC-DC and DC-AC stages.

Main Methods:

• The proposed architecture utilizes a modular arrangement of identical buck-boost cells.
• Three cells synthesize DC-biased sinusoidal phase voltages for the AC output.
• A fourth cell regulates the DC output and establishes the AC neutral, creating a common ground reference without galvanic isolation.

Main Results:

• The converter successfully delivered 1 kW to the three-phase AC port and 800 W to the DC port simultaneously.
• Simulations and laboratory measurements verified stable DC regulation and balanced sinusoidal AC waveforms.
• Fast, well-damped responses were observed under both AC and DC load steps at a 62.5 kHz switching frequency.

Conclusions:

• The proposed modular dual-output hybrid converter offers a feasible, single-stage solution for hybrid microgrids.
• This topology enhances efficiency and simplifies integration by providing simultaneous AC and DC power delivery.
• The MUC advancement contributes to the standardization and modularity of power electronic converters in next-generation power systems.