The invention discloses a selectively passive compensated pulsed alternator, which consists of a spindle, a rotor, an exciting winding, a self-closing compensating winding, an armature winding, an unslotted stator, a machine shell, a front end cover, a back end cover, an electric brush and a collecting ring, wherein the exciting winding is arranged in a rotor groove to realize rotating excitation; the self-closing compensating winding is fixed on the rotor, and the armature winding is fixed on the inner surface of the unslotted stator; the stator is fixed in the machine shell; the front end cover and the back end cover are arranged on two ends of the machine shell; the spindle penetrates through the rotor and the axes of the end covers to play a role of supporting; and at the same time the end part of the spindle is provided with the electric brush and the collecting ring. According to the selectively passive compensated pulsed alternator, the output performance of the compensated pulsed alternator is improved, and the application field is extended.