Frequency and voltage control of micro hydro power stations based on hydraulic turbine's linear model applied on induction generators

This paper presents an approach to full modeling and control of micro hydro power stations using linear model of hydraulic turbine applied on induction generators. Constant frequency control is obtained by a speed governor applied in turbine feed system while constant voltage control is reached through reactive power control by a voltage-source inverter (VSI). In order to reach effective frequency control it is proposed the use of motor flux estimation algorithm to obtain the measurement of instantaneous rotor speed without the necessity of mechanical sensor applied on his shaft, resulting in inherent cost reduction. Simulation results, considering step changes in load and frequency reference setting, have been considered. Experimental results related to reactive power control and voltage regulation are presented and have shown satisfactory dynamic performance.