说明：  DFIG system, including a wind turbine, a generator, power electronic converters and power system grid are modeled. All of the control algorithms and operation modes are simulated. The active power is always controlled at maximum output while the reactive power is controlled to achieve a particular power factor or line voltage. Second, a complete DFIG wind power test bench including a wind turbine emulator is designed and built. The back-to-back converters are designed to control the DFIG. A Microchip d