Grid-connected Control Strategies for a Dual Power Flow Wind Energy Conversion System

A novel dual power flow (DPF) wind energy conversion system (WECS) based on an electrical variable transmission (EVT) machine is proposed recently. The structure of the novel EVT-based WECS, especially the grid-connected configuration, is different from any other existing WECSs. In this paper, the grid-connected control strategies of the DPF- WECS are proposed by controlling the DC-link and the inner rotor side converter, where the DC-link with and without the energy storage system (ESS) is considered separately. The relevant control strategies are presented to enhance the grid fault ride through capability of the DPF-WECS. Moreover, the maximum power point tracking control strategy and the pitch control strategy are also studied to implement the complete functionality of the DPF-WECS. The simulation model of the DPF-WECS is developed based on the EVT mathematical models and proposed control strategies. Finally, the simulation results verify the efficiency of the proposed control strategies for the DPF-WECS.