A PWM Multilevel Current-Source Inverter Used for Grid-Connected Wind Energy Conversion System

This paper proposes a grid-connected wind energy conversion system (WECS) based on a PWM multilevel currentsource inverter (MCSI) topology. The topology used here is derived from the multilevel voltage-source inverter (MVSI) by dual conversion, this allows the wealth of existing knowledge relating to the operations, modulations and control strategies of multilevel VSI to be immediately applied to such multilevel CSI. The topology are supplied with two independent DC current-sources, 2n+1 current levels are obtained at the output. In the proposed control scheme, DC-link current controller is used to regulate and stabilize dc link current, output power factor controller is used to independently control the real power or reactive power, and unity power factor is easily achieved at grid side. Validation of models, control and steady-state and transient performances of a WECS based on 5-level CSI is carried out in the MATLAB/Simulink environment.