Corresponding author: Aouini Raouia , email: aaouinii@yahoo.com 1 Université de Tunis El Manar, Ecole Nationale d’Ingénieurs de Tunis, LR11ES15 Laboratoire des Systèmes Electriques, 1002 Tunis, Tunisia Copyright © JES 2017 on-line : journal/esrgroups.org/jes Raouia Aouini 1 , Ichrak Nefzi 1 , Khadija Ben Kilani 1 , Mohamed Elleuch 1 J. Electrical Systems 13-3 (2017): 543-557 Regular paper                                                                                                                                               !" ! #        "                      !           Keywords: Photovoltaic systems; Wind Energy generation; Synchronverter; GCR; Voltage oriented control Article history: Received 3 July 2017, Accepted 21 August 2017 1. Introduction Modern power grids are characterized by large scale penetration of renewable energies and less reliance on fossil fuels [1]-[2]. The most exploited renewable energies are hydroelectric, photovoltaic (PV), and wind. The share of renewable in global electricity production is steadily increasing. The world’s renewable energy production share will be increased to 20% by the year 2020 [3]. However, 16% is due to hydroelectric energy production; hence, wind and PV (the most promising renewable sources) energy production is still very modest [3]. However, these two most promising renewable energies have different requirements. Compared to hydraulic power, wind and PV energies are Variable Renewable Energy (VRE) sources, and their integration into power grids open operational issues in power grid [4]-[5]. Indeed, VRE has direct implication on system operation and stability. Their integration is achieved using power electronic converters and hence, the control design of power converter-fed units connected to the grid has become a major issue in control and power research communities. These generator concepts differ significantly from conventional sources in terms of performances during grid faults, emission of harmonic currents or inherent response to frequency changes. The current trend is that renewable sources must comply with the system operators ancillary services, such as voltage and frequency controls. Grid codes provide the rules for the power system and energy market operation, ensuring operational stability and security of power supply [5]. The function of a grid connection code covering VRE is to