Analysis of a Control System for DFIG Wind Generators Based on the Transmission of Power References through a GSM Wireless Network: A Smart Grid Experimental Approach  
[PERSON]  
1 Laboratory of Advanced Electric Grids (Polytechnic School), University of Sao Paulo (USP), Sao Paulo 05508-010, Brazil; [EMAIL_ADDRESS] (L.A.G.G. ); [EMAIL_ADDRESS] (M.B.C.S.) 2 Department of Automation and Process Control, Federal Institute of Sao Paulo (IFSP Suzano), Sao Paulo 08673-010, Brazil  
3 Center for Engineering, Modeling and Applied Social Sciences (CECS), Federal University of ABC (UFABC), Santo Andre 09210-580, Brazil; [PERSON]SS] (A.L.L.F.M. ); [PERSON](H.S.F. ); [PERSON]SS] (J.A.T.A. ); [EMAIL_ADDRESS] (A.J.S.F. ); [EMAIL_ADDRESS] (C.E.C. ); [EMAIL_ADDRESS] (I.R.S.C.) 4 Center for Engineering, Modeling and Applied Social Sciences (CECS), Federal University of ABC (UFABC), Santo Andre 09210-580, Brazil; [PERSON]L_ADDRESS]om (A.L.L.F.M. ); [PERSON](H.S.F. ); [EMAIL_ADDRESS] (J.A.T.A. ); [EMAIL_ADDRESS] (A.J.S.F. ); [EMAIL_ADDRESS] (C.E.C. ); [EMAIL_ADDRESS] (I.R.S.C.) 5 Center for Engineering, Modeling and Applied Social Sciences (CECS), Federal University of ABC (UFABC), Santo Andre 09210-580, Brazil; [PERSON]SS] (A.L.L.F.M. ); [PERSON](H.S.F. ); [EMAIL_ADDRESS] (J.A.T.A. ); [EMAIL_ADDRESS] (A.J.S.F. ); [EMAIL_ADDRESS] (C.E.C. ); [EMAIL_ADDRESS] (I.R.S.C.) 6 October 201827 December Regarding the use of wind energy, an interesting solution is the use of Doubly Fed Induction Generators (DFIGs) connected to the grid [6; 7; 8; 9]. This type of machine presents some important advantages, such as operation in four quadrants and processing of only 25% to 30% of its nominal power by the converter, while other electrical machines, such as the Switched Reluctance Generator (SRG), Squirrel Cape Induction Generator (SCIG), and Synchronous Generator (SyG) process full power by the converter [10; 11; 12]. In a traditional DFIG scheme, a back-to-back converter connects the rotor of the generator to the power grid, while the stator is directly connected to the main grid [13; 14]. The converter enables power flow between the DFIG and the grid by applying three-phase voltage on the rotor side [15]. In addition, the converter connected to the grid controls the DC link and enables the absorption or injection of power to the grid, in accordance with the DFIG speed. The performance of the power flow can be increased by using control strategies, such as Stator Flux Oriented (SFO) or Stator Voltage Oriented (SVO) [12]. These strategies allow the control of active (\(P\)) and reactive (\(Q\)) powers of the stator that are injected into the grid by adjusting the rotor current, by means of Proportional Integral (PI) [16], predictive [17], deadbeat [7; 18], or sliding mode [19] controllers. On the other hand, wireless communication technologies have become quite popular in power system applications in the last decade [19; 20; 21]. This trend is explained by their increasing reliability, reduced cost, easy maintenance, high speed, and flexibility of connection between different devices [22; 23; 24; 25]. In the literature, it is possible to find several studies about wireless systems in the control of renewable energy systems [10; 26; 27; 28; 29; 30; 31]. Despite the inherent difficulties of transmitting signals through wireless channels such as noise, interferences, and multipath fading, the use of wireless systems has become increasingly attractive, especially with the materialization of the SG [32]. In this context, this work analyzes the performance of a DFIG power control system, considering that the power references are transmitted from the SG Control Center (CC) to the wind generator by a mobile communication network infrastructure, as shown in Figure 1. In order to reduce the implementation time and operation costs of the wireless control system, it is proposed and adopted to use the automatic Short Message Service (SMS) of a Global System for Mobile Communication (GSM) network to transmit the power references.