Self-excited induction generator controlled by a VS-PWM converter providing high power-factor current to a single-phase grid

This paper is concerned with the application of a three-phase cage induction machine as a self-excited hydraulic-turbine driven generator connected to the AC side of a voltage source PWM bi-directional power converter. Frequency and voltage at the three-phase AC load are regulated by the action of the PWM converter. This structure also provides energy to the utility grid via a buck converter and a current inverter connected to a single-phase AC line. The buck converter is controlled by a power factor corrector IC so that a sinusoidal current is sent to the utility with unity power factor. The proposed system is intended to be applied in rural plants as source of three-phase voltage with regulated frequency and amplitude. The generator is intended to be driven by a low-head hydraulic turbine with an unregulated shaft, resulting in a system with relative low-cost