Advances in the modelling and control of micro hydro power stations applied on self-excited induction generators based on hydraulic turbine nonlinear model

This chapter proposes a solution for the control of micro hydro power stations for island operation based on the characteristics of hydraulic turbine nonlinear model with the use of a self-excited induction generator. To control the frequency of the turbine it was considered the non-linear model applied to this type of turbine and the use of a frequency regulator, with characteristics of a proportional-derivative controller (PD), applied to the control of a system, which is composed by a three-phase induction motor driven by a frequency inverter. Voltage control is performed through a voltage fed inverter with pulse width modulation (PWM). The PWM inverter operates as a static VAR compensator absorbing or injecting reactive power in the system according to the load connected on its terminal in order to regulate the voltage at the terminals of the induction generator. The proposed control system is implemented digitally using a digital signal processor (DSP). Also, along this chapter, simulation and experimental results are presented in order to demonstrate the action of the control system in the regulation of variables of the generation system, both in terms of frequency control and voltage control.