This paper presents a comparative analysis between three control techniques based on the Direct Power Control (DPC) algorithm for grid-tied Voltage Source Inverters (VSI). These techniques are used to regulate the injection of instantaneous active and reactive powers in a power system for renewable generation system applications. The first technique corresponds to the Classical DPC (C-DPC) and it is based on the definition of a Virtual Flux (VF). In the second one, the instantaneous active and reactive powers are estimated by using the time derivatives of the injected currents, without any voltage sensors. The third algorithm uses the Space Vector Modulation (SVM) technique to generate additional space vectors and it considers the minimum square error of the instantaneous active and reactive powers to determine the switching states. Simulation results of the three control techniques are presented and their performance is compared based on some criteria such as maximum steady-state power error, the current total harmonic distortion and the rise time.