Model-Free Robust Control of Current-Speed for Marine Propulsion Six-Phase PMSM Based on Composite Virtual Vectors

To improve the current tracking accuracy and system robustness of traditional Virtual Vector Model Predictive Control (VVMPC) in the fundamental plane of a Six-Phase Permanent Magnet Synchronous Motor (Six-Phase PMSM), this paper proposes a model-free robust current-speed control method based on Composite Virtual Vectors (CVV) for ship propulsion Six-Phase PMSM. First, 12 elementary virtual vectors are extended to synthesize the novel composite virtual vector (CVV), which enhances the current tracking performance in the fundamental plane. Next, to improve the robustness of the drive system, an Extended State Observer-Ultra Local Model (ESO-ULM) is designed in the current loop. Additionally, in the speed loop, an independent ULM sliding mode speed controller is constructed based on Model-Free Control (MFC) theory, replacing the traditional PI regulator. Finally, simulation validation is conducted under a simulated ship propeller characteristic load environment. The results demonstrate that, compared to traditional VVMPC, the proposed method exhibits better robustness to motor parameter variations and step load changes.