Wind-driven power generating system and excitation unit of direct-current brushless synchronous wind-driven power generator

The utility model discloses an excitation unit of a direct-current brushless synchronous wind-driven power generator, which is used for a wind-driven power generating system and comprises a first rectifying circuit, a control portion and an excitation power output portion. The first rectifying circuit outputs direct-current input voltage after alternating-current input voltage is rectified by the same. The control portion can detect excitation voltage and excitation current of an exciter, direct-current output voltage output by a converter of the power generating system, output voltage of any two optional phases of a stator winding of a main generator and present rotating speed of the power generator, output PWM (pulse width modulation) waves to the excitation power output portion by the aid of inner ring control of the excitation current and outer ring control of the direct-current output voltage and adjust the excitation current transmitted to the power generator. The direct-current input voltage is inverted by the excitation power output portion according to the PWM waves and is rectified into the direct-current excitation current, and the direct-current excitation current is output to a stator winding of the exciter of the power generator. According to the above structure, by adjusting capacity of the excitation current transmitted to the power generator, stable voltage output of the power generator is realized and stability of the electric power system is guaranteed.