The wind emulator reproduces the wind force on a shaft, when the speed it is programmed. It is possible a static programming of the shaft speed or torque , as well as dynamic by means of a ramp. Two electrical generators are connected to the shaft (a induction generator and permanent magnet generator). A power electronic converter connects the generators to the grid or to a load, enabling all types of tests. The power electronic converter controls the generator and it is based on three-level converters in a back-to-back connection.