Small wind turbine incremental current based MPPT with current control for grid-connected DC microgrid application

Abstract

This paper presents an incremental-type current based Maximum Power Point Tracking (MPPT) system for a small wind turbine (SWT) connected to a grid-connected DC microgrid. The proposed MPPT algorithm calculates the required current, according to the increase or decrease in the DC link voltage, to obtain maximum power transfer to the DC microgrid at all wind speeds. The calculated current value by the MPPT algorithm is used as a reference current for a Proportional Integral (PI) current controller which controls the inductor current in the boost converter connecting the system to the DC microgrid. The proposed MPPT algorithm offers the advantage of requiring less computational calculations, since it uses only the measured DC link voltage, without the need to calculate the DC link power. The proposed MPPT algorithm was simulated on a modelled system consisting of a Permanent Magnet Synchronous Generator (PMSG) driven by a SWT, which was interfaced to the DC microgrid through a rectification stage and a boost converter. The MPPT system, the boost converter, and current control are explained in detail. Simulation results of the system operating under varying wind conditions are presented to highlight the performance of the developed MPPT algorithm.