Passivity-based Sliding-mode Control Strategy Based on Hexagonal Converter

It is not so ideal to apply a hexagonal converter (Hexverter) to offshore wind power when it is controlled by the linear PID control due to its own nonlinear characteristics, the randomness of the renewable energy, and the ingestion of the system parameters. In this paper, based on the non-linear passivity-based control (PBC), the passivity and stability of the Hexverter are analyzed. Combining with the sliding mode control (SMC) to compensate for the shortcomings of using the passivity-based control alone, a passivity-based sliding-mode composite control (PBC+SMC) for the Hexverter is proposed. The Hexverter PBC+SMC simulation system is built on MATLAB, and a variety of different working conditions are simulated. The simulation results of the PBC+the SMC, the PBC, and the PID are compared, which verifies that the proposed composite control strategy has a better steady state and dynamic performance with faster response, stronger robustness, and lower harmonic content compared with the other two control strategies. It can achieve different control objectives under the unbalanced grid conditions according to different requirements. © 2023 Power System Technology Press. All rights reserved.