Induction generators are widely used to generate electrical power in small hydraulic applications. The main disadvantage of stand- alone induction generators is the problem of regulating the voltage magnitude and voltage frequency under load variation. This paper investigates a three-phase self-excited induction generator (SEIG) operating under varying load, utilizing the water energy in a small reservoir hydropower plant. The generator excitation is provided by a three-phase capacitor bank and an inverter with Space Vector Pulse Width Modulation (SVPWM). Furthermore, the inverter with a battery controls the active power flow between the generator and the load in order to provide a constant frequency of voltage. The proposed control scheme consists of two PI controllers. The first controls the voltage magnitude by regulating the inverter reactive power, while the second one adjusts the guide vanes of the turbine according to the DC voltage of the battery. The proposed control system has been tested under load step changes. The simulation results of the system, obtained using the Matlab/Simulink software, have demonstrated good control performance.

Induction generators are widely used to generate electrical power in small hydraulic applications. The main disadvantage of stand- alone induction generators is the problem of regulating the voltage magnitude and voltage frequency under load variation. This paper investigates a three-phase self-excited induction generator (SEIG) operating under varying load, utilizing the water energy in a small reservoir hydropower plant. The generator excitation is provided by a three-phase capacitor bank and an inverter with Space Vector Pulse Width Modulation (SVPWM). Furthermore, the inverter with a battery controls the active power flow between the generator and the load in order to provide a constant frequency of voltage. The proposed control scheme consists of two PI controllers. The first controls the voltage magnitude by regulating the inverter reactive power, while the second one adjusts the guide vanes of the turbine according to the DC voltage of the battery. The proposed control system has been tested under load step changes. The simulation results of the system, obtained using the Matlab/Simulink software, have demonstrated good control performance.