Modulated Predictive Current Control of PMSG-Based Wind Energy Systems

This paper presents an efficient modulated model predictive current control for direct driven wind energy system composed of surface-mounted permanent magnet synchronous generator and back-to-back connected voltage source converter. The proposed control method fulfils the generator-side control requirements such as maximum power point tracking, and grid-side control objectives such as DC-link voltage control and power factor correction. These objectives are achieved through the regulation of generator and grid currents with fast transient response, smooth steady-state and fixed switching frequency operation simultaneously. The proposed controller predicts the future behavior of generator and grid currents using quasi-exact discrete-time models and eight voltage vectors, and then evaluates them by two independent cost functions. Finally, the switching sequence is designed by the space vector modulation using three stationary voltage vectors corresponding to the optimal cost function. The performance of the proposed method is validated through the MATLAB simulations using a 750-kW wind energy system at different wind speeds and grid reactive powers.