Abstract: The diode-clamped three-level rectifier which is suitable for Direct-drive wind turbine system is presented, the operating mode of the rectifier is analyzed, and a SVPWM control method which is based on the average model of PWM rectifier and tracked instruction voltage vector is derived in detail. The simulation results show that the harmonics is suppressed effectively, the distortion of AC current waveforms is decreased, the power factor can be adjusted, and the bi-direction flowing of energy is implemented.

Key words: direct-driving wind power system, rectifier, SVPWM, three levels, diode-clamped