MOSFET-Oriented Current Sharing Control Strategy for Scalable Parallel DC/DC Converters

Area of Science:

• Electrical Engineering
• Power Electronics

Background:

• Parallel DC/DC converter modules are crucial for power scalability.
• MOSFET parameter mismatches and module inconsistencies can cause load current imbalance in parallel systems.

Purpose of the Study:

• To propose and validate a three-loop current-sharing control strategy for parallel MOSFET-based lagging leg series diodes phase-shift full-bridge (LLSD-PSFB) converters.
• To mitigate load current imbalance and improve the coordinated operation of parallel converter modules.

Main Methods:

• Analysis of the operating principle and parameter design of a single-module LLSD-PSFB converter.
• Establishment of an averaged model and derivation of a small-signal model for the parallel system.
• Development and validation of a three-loop control strategy (voltage, current, and current-sharing loops).

Main Results:

• The proposed control strategy effectively improves current-sharing accuracy and dynamic response.
• Simulation results validated the effectiveness of the control scheme.
• Experimental results confirmed high current-sharing precision and stable operation of the parallel system.

Conclusions:

• The three-loop control strategy is effective for parallel DC/DC converter systems.
• The strategy demonstrates potential for scalable high-power applications by ensuring stable operation and precise current sharing.