Sensorless Control of Permanent Magnet Synchronous Marine Current Generator Based on Inverse Quadratic Interpolation Finite‐Position‐Set Phase‐Locked Loop

ABSTRACT Marine current turbines (MCTs) are frequently affected by variations in marine current velocity, swell disturbances, and load torque fluctuations. These disturbances can cause rapid changes in the operating state of the permanent magnet synchronous generator (PMSG). Therefore, fast rotor position estimation is crucial for the sensorless control of PMSG‐based marine current power generation systems. Finite‐position‐set phase‐locked loop (FPS‐PLL) has attracted increasing attention in such systems due to its excellent dynamic response. However, it suffers from a high computational burden. To address this problem, an inverse quadratic interpolation FPS‐PLL (IQI‐FPS‐PLL) is proposed in this paper. In this method, a half‐angle octant method is developed. The rotor position domain is divided into eight sectors. Then, accurate rotor position estimation can be achieved with only one IQI calculation. Finally, the proposed IQI‐FPS‐PLL is implemented and validated on both a MATLAB/Simulink simulation platform and an 11‐kW PMSG experimental platform. The results verify the effectiveness of the proposed method.