Simple control scheme of three-level PWM converter connecting wind turbine with grid

Abstract

This paper proposes a simple direct power control using space vector modulation (DPC-SVM) for three-phase three-level neutral point clamped (3L-NPC) PWM converter connecting a wind turbine generator with grid. The active and reactive power are used as the control variables instead of the currents applied in conventional control method. Moreover, grid voltage sensors are replaced by a virtual flux (VF) estimator. The theoretical principle of this method as well as the synthesis of the active and reactive power controllers are discussed. It is shown that the proposed method exhibits several features as: simple and robust algorithm as well as simple tuning procedure of PI power controllers. Furthermore the paper presents a LCL-filter design, which fulfils IEEE-SCR 20-50 recommendation. Simulation results have proven an excellent performance and verified the validity of the proposed system.