Model-Free Predictive Control Based on Recursive Least Square and Quadratic Interpolation Methods Applied to Power-Hardware-in-The-Loop Simulation

Power-hardware-in-the-loop (PHIL) is a form of real-time simulation that allows a real power device to interact with a simulated power system. In PHIL simulation, the power equipment under test (PEUT) is connected to a real-time digital simulator via a power amplifier and an interface algorithm. A switched-mode power amplifier (SMPA) is commonly employed in the PHIL application due to its wide range of applications from small-scale to mega-watt ranges. However, it is known to have slow dynamic response. This article applies model-free predictive current control (MFPCC) based on the recursive least square method combined with Newton's quadratic interpolation to improve the dynamic response of a SMPA. The control algorithms are implemented in the SMPA in an actual PHIL setup to verify the performance of the proposed control method. The results show that the proposed MFPCC yields more accurate results, wider stability regions, and quicker response compared to the existing SMPA controllers in the PHIL. In addition, the proposed model is able to reproduce the harmonic distortions of a bus to the PEUT when the bus of the power network being simulated is subjected to harmonic distortions. Moreover, compared to some existing MFPCCs, the proposed controller can maintain PHIL stability even if multiple time step delays exist in the loop while the former yields instability.