An Improved Mechanical Sensorless Maximum Power Point Tracking Method for Permanent-Magnet Synchronous Generator-Based Small Wind Turbines Systems

Abstract

This article proposes an improved maximum power point tracking (MPPT) method without mechanical and voltage sensors for small wind turbines (SWT) systems. The technique is suitable for SWT systems that employ a permanent-magnet synchronous generator (PMSG), a three-phase diode bridge rectifier, and a dc–dc converter, which is one of the most popular configuration for this kind of system. The proposed MPPT extracts the maximum available power from the PMSG operating with variable speed, and it is based on the output power characteristic in relation to the output current of the rectifier. The article proves that a constant output current in the rectifier ensures extracting the maximum electrical power available in the SWT system, independent of the rotational speed. Additionally, this constant current value depends solely on the PMSG characteristics. Therefore, the proposed MPPT control strategy is a simple current mesh with a constant reference that is implemented in a dc–dc converter connected in series to the rectifier, which is responsible to guarantee a constant current in the rectifier output. The proposed MPPT method was corroborated through simulation and experimental results in a 1.5-kW SWT. The tracking efficiency of the proposed MPPT was close to 97.64%.