This paper presents a new optimization technique for simultaneous tuning of the parameters into the controllers associated with the control voltage oscillation and damping in synchronous generators. The parameters of the Automatic Voltage Regulator - AVR and the Power System Stabilizer – PSS are optimized thought a modification proposed in the Modified Particle Swarm Optimization technique (called MPSO - Modified Particle Swarm Optimization). To analyze the performance of the controllers, an objective function was used, based on system time response to a variation in the reference voltage of the machine. The parameters obtained for AVR and PSS are compared with the values ​​calculated by the conventional adjustment technique and by the MPSO technique. The results of the simulation show that the technique proposed was efficient in tuning the AVR and PSS parameters, highlighting its ...