Modulated Predictive Current Control of NPC Converter-Based PMSG Wind Energy System

In this paper, an efficient modulated model predictive current control of back-to-back connected neutral-point clamped (NPC) converter in direct-driven surface-mounted permanent magnet synchronous generator-based variable-speed wind energy conversion system is presented. The proposed control scheme fulfils the wind energy requirements such as maximum power point tracking, control of neutral-point voltage and grid reactive power regulation through the control of generator and grid currents with fast transient response, smooth steady-state and fixed switching frequency operation simultaneously. The three voltage vectors corresponding to the optimal cost functions of NPC rectifier and inverter are synthesized by the space vector modulation with active control of dwell times to balance the DC capacitors voltage. To evaluate the proposed control scheme, dynamic simulation results are presented for a 3 MW and 3000 V wind turbine under varying wind speed conditions.