Dynamic Modeling of Hybrid Generator-Based Wind Energy Conversion System

This paper presents the modeling and control of a grid-integrated wind generation system that incorporates a direct-drive multiphase high voltage hybrid generator (HG) interfaced to a multi-leg passive rectifier, and a grid-side voltage source converter (VSC-G). The HG has a dual rotor structure with a permanent magnet (PM) rotor and wound field (WF) rotor that facilitates active control over the DC-link voltage between the passive rectifier and the VSC. As such, unlike the existing schemes the DC-link voltage is not controlled by the VSC allowing it to have a further degree of control freedom. A comprehensive dynamic model of the wind generation system including the wind turbine (WT), HG, passive rectification, and VSC is developed that is used for the proposed control studies. The proposed control strategy includes DC-link voltage control implemented by the HG, and d-q control for the VSC-G. The implemented control strategy facilitates optimal power transfer from the wind turbines (WTs) to the AC grid, showing excellent dynamic performance in steady-state and transient operation. Through extensive simulations, the study investigates the system's response to varying wind velocities and different load conditions, highlighting its ability to accurately regulate the voltage at DC-link and precisely control both active and reactive powers.