Comparison of SVM and DPC for reactive power control of DFIG based wind energy systems

Abstract

This paper presents the Comparative Analysis of the two different control strategies Space Vector Modulation (SVM) and Direct Power Control (DPC) being applied to a Doubly fed Induction Generator (DFIG) based wind energy generation system. The key approach of the SVM is to obtain the reference voltage of modulator. However this approach requires PI regulators together with coordinated transformation. These will complicate the system and also the steady-state and transient performance are highly sensitive to the PI control parameters and for ensuring the system stability more tuning efforts are required. In DPC approach, the converter switching states are selected directly by the instantaneous active and reactive power based on Hysteresis comparators. The main advantage of the DPC control is that it does not require the use of coordinated transformations and modulation techniques which will reduce the harmonics and also increase the efficiency of the system. In this paper the simulation results are presented for 9 MW DFIG based wind turbine system. The simulation results confirms that the DPC control strategy provides fast, accurate and decoupled power control when compared to SVM.