Application of bidirectional switches in the development of a voltage regulator for self-excited induction generators

This study presents a voltage regulator that is specific to three-phase self-excited induction generators (SEIG). The voltage regulator proposed in this paper uses a PID controller that adjusts the pulse width of a PWM signal for the firing of the bidirectional switches, which provides the switching function of an inductive load that consumes reactive energy, thus controlling the terminal voltage of the SEIG. The paper presents the results obtained by means of computer simulation and experiments. In order to demonstrate the operation of this regulator, the tests present a critical operational condition, the triggering of a dynamic load, where SEIG of 3 hp supplies the direct start-up of a 1 hp induction motor. Even under this worse condition scenario, the regulator manages to recuperate the terminal voltage of the generator to a permitted voltage regulation value (1.02 pu).