Utilization of Power Hardware-in-the-Loop to Study Power Conversion Topologies and Control in Distributed Generation Power Systems

Future isolated DC microgrids are looking to adopt a hybrid-electric, medium voltage DC, zonal topology for benefits in redundancy and reliability. In order to best design these extensive power systems, real-time compatible models of multi-pulse rectifiers converting 3-phase AC power from rotating machines to DC were developed. Developing models in the context of real-time simulation for power hardware-in-the-loop applications has inherent limitations. An initial limitation of linear models inaccurately predicting 3-phase power quality was observed in previous work and was further constrained by inherent modeling limitations within a real-time simulator. Transformer hysteresis was approximated with a proposed function that was optimized using an iterative gradient descent algorithm. Implementing the approximated nonlinear models resulted in a significant improvement in the model's ability to predict the power quality seen in experimental data, and results in a valid Simulink-based rectifier model for real-time simulation over a large region of operation.